bluuebunny/crossref_metadata_2025_split huggingface dataset:
Joziknipholones A and B: The First Dimeric Phenylanthraquinones, from the Roots of Bulbine frutescens
Authors: Bringmann Gerhard , Mutanyatta‐Comar Joan , Maksimenka Katja , Wanjohi John M. , Heydenreich Matthias , Brun Reto , Müller Werner E. G. , Peter Martin G. , Midiwo Jacob O. , Yenesew Abiy 
Published: December 2007

AbstractFrom the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and ‐anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P‐configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M‐configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells.
Electrochemical Insights into the Mechanisms of Proton Reduction by [Fe2(CO)6{μ‐SCH2N(R)CH2S}] Complexes Related to the [2Fe]H Subsite of [FeFe]Hydrogenase
Authors: Capon Jean‐François , Ezzaher Salah , Gloaguen Frédéric , Pétillon François Y. , Schollhammer Philippe , Talarmin Jean 
Published: December 2007

AbstractElectrochemical investigations on a structural analogue of the [2Fe]H subsite of [FeFe]H2ases, namely, [Fe2(CO)6{μ‐SCH2N(CH2CH2‐ OCH3)CH2S}] (1), were conducted in MeCN/NBu4PF6 in the presence of HBF4/Et2O or HOTs. Two different catalytic proton reduction processes operate, depending on the strength and the concentration of the acid used. The first process, which takes place around −1.2 V for both HBF4/Et2O and HOTs, is limited by the slow release of H2 from the product of the {2 H+/2 e} pathway, 1‐2H. The second catalytic process, which occurs at higher acid concentrations, takes place at different potentials depending on the acid present. We propose that this second mechanism is initiated by protonation of 1‐2H when HBF4/Et2O is used, whereas the reduction of 1‐2H is the initial step in the presence of the weaker acid HOTs. The potential of the second process, which occurs around −1.4 V (reduction potential of 1‐3H+) or around −1.6 V (the reduction potential of 1‐2H) is thus dependent on the strength of the available proton source.
Calcium‐fluxing glutamate receptors associated with primary gustatory afferent terminals in goldfish (Carassius auratus)
Authors: Huesa Gema , Ikenaga Takanori , Böttger Bärbel , Finger Thomas E. 
Published: December 2007

AbstractPresynaptic ionotropic glutamate receptors modulate transmission at primary afferent synapses in several glutamatergic systems. To test whether primary gustatory afferent fibers express Ca2+‐permeable AMPA/kainate receptors, we utilized kainate‐stimulated uptake of Co2+ along with immunocytochemistry for the Ca2+‐binding proteins (CaBPs) calbindin and calretinin to investigate the primary gustatory afferents in goldfish (Carassius auratus). In goldfish, the primary gustatory nucleus (equivalent to the gustatory portion of the nucleus of the solitary tract) includes the vagal lobe, which is a large, laminated structure protruding dorsally from the medulla. Kainate‐stimulated uptake of Co2+ (a measure of Ca2+‐fluxing glutamate receptors) shows punctate staining distributed in the distinct laminar pattern matching the layers of termination of the primary gustatory afferent fibers. In addition, CaBP immunocytochemistry, which correlates highly with expression of Ca2+‐permeable AMPA/kainate receptors, shows a laminar pattern of distribution similar to that found with kainate‐stimulated cobalt uptake. Nearly all neurons of the vagal gustatory ganglion show Co2+ uptake and are immunopositive for CaBPs. Transection of the vagus nerve proximal to the ganglion results in loss of such punctate Co2+ uptake and of punctate CaBP staining as soon as 4 days postlesion. These results are consonant with the presence of Ca2+‐fluxing glutamate receptors on the presynaptic terminals of primary gustatory terminals, providing an avenue for modulation of primary gustatory input. J. Comp. Neurol. 506:694–707, 2008. © 2007 Wiley‐Liss, Inc.
Synapses between corticotropin‐releasing factor‐containing axon terminals and dopaminergic neurons in the ventral tegmental area are predominantly glutamatergic
Authors: Tagliaferro Patricia , Morales Marisela 
Published: December 2007

AbstractInteractions between stress and the mesocorticolimbic dopamine (DA) system have been suggested from behavioral and electrophysiological studies. Because corticotropin‐releasing factor (CRF) plays a role in stress responses, we investigated possible interactions between neurons containing CRF and those producing DA in the ventral tegmental area (VTA). We first investigated the cellular distribution of CRF in the VTA by immunolabeling VTA sections with anti‐CRF antibodies and analyzing these sections by electron microscopy. We found CRF immunoreactivity present mostly in axon terminals establishing either symmetric or asymmetric synapses with VTA dendrites. We established that nearly all CRF asymmetric synapses are glutamatergic, insofar as the CRF‐immunolabeled axon terminals in these synapses coexpressed the vesicular glutamate transporter 2, and that the majority of CRF symmetric synapses are GABAergic, insofar as the CRF‐immunolabeled axon terminals in these synapses coexpressed glutamic acid decarboxylase, findings that are of functional importance. We then looked for synaptic interactions between CRF‐ and DA‐containing neurons, by using antibodies against CRF and tyrosine hydroxylase (TH; a marker for DA neurons). We found that most synapses between CRF‐immunoreactive axon terminals and TH neurons are asymmetric (in the majority likely to be glutamatergic) and suggest that glutamatergic neurons containing CRF may be part of the neuronal circuitry that mediates stress responses involving the mesocorticolimbic DA system. The presence of CRF synapses in the VTA offers a mechanism for interactions between the stress‐associated neuropeptide CRF and the mesocorticolimbic DA system. J. Comp. Neurol. 506:616–626, 2008. Published 2007 Wiley‐Liss, Inc.
Iridium Thin Films Deposited by Liquid Delivery MOCVD using Ir(EtCp)(1,5‐COD) with Toluene Solvent
Authors: Ritterhaus Y. , Hur'yeva T. , Lisker M. , Burte E. P. 
Published: December 2007

AbstractPure iridium thin films are prepared using iridium(ethylcyclopentadienyl)(1,5‐cyclooctadiene) [Ir(EtCp)(1,5‐COD)] with toluene solvent by liquid delivery metal‐organic (MO)CVD. The deposition of Ir thin films is carried out on various substrates at temperatures in the range 300 – 500 °C via the oxygen‐assisted pyrolysis of the precursor. The reaction kinetics, film composition, film morphology, mechanical and electrical properties of deposited Ir films are investigated. Annealing in an oxidizing atmosphere at temperatures above 700 °C results in an increased oxidation of the films, as proven by X‐ray diffraction (XRD) analyses. Obtained films show a low resistivity of 7 μΩ·cm and preferred crystalline orientation (111), suitable for application in storage capacitor electrodes.
Leukaemia in young children living in the vicinity of German nuclear power plants
Authors: Kaatsch Peter , Spix Claudia , Schulze‐Rath Renate , Schmiedel Sven , Blettner Maria 
Published: December 2007

AbstractA case control study was conducted where cases were children younger than 5 years (diseased between 1980 and 2003) registered at the german childhood cancer registry (GCCR). Population‐based matched controls (1:3) were selected from the corresponding registrar's office. Residential proximity to the nearest nuclear power plant was determined for each subject individually (with a precision of about 25 m). The report is focused on leukaemia and mainly on cases in the inner 5‐km zone around the plants. The study includes 593 leukaemia cases and 1,766 matched controls. All leukaemia combined show a statistically significant trend for 1/distance with a positive regression coefficient of 1.75 [lower 95%‐confidence limit (CL): 0.65]; for acute lymphoid leukaemia 1.63 (lower 95%‐CL: 0.39), for acute nonlymphocytic leukaemia 1.99 (lower 95%‐CL: −0.41). This indicates a negative trend for distance. Cases live closer to nuclear power plants than the randomly selected controls. A categorical analysis shows a statistically significant odds ratio of 2.19 (lower 95%‐CL: 1.51) for residential proximity within 5 km compared to residence outside this area. This result is largely attributed to cases in previous studies of the GCCR (especially in the inner zone) as there is clearly some overlap between those studies. The result was not to be expected under current radiation‐epidemiological knowledge. Considering that there is no evidence of relevant accidents and that possible confounders could not be identified, the observed positive distance trend remains unexplained. © 2007 Wiley‐Liss, Inc.
Cytobiocompatibility of collagen and ePTFE membranes on osteoblast‐like cells in vitro
Authors: Friedmann Anton , Dehnhardt Jasmin , Kleber Bernd‐Michael , Bernimoulin Jean‐Pierre 
Published: December 2007

AbstractIn guided bone regeneration (GBR), a semipermeable membrane is placed over an osseous defect to create a secluded environment in which bone formation can proceed without ingrowth of connective tissue cells from the overlaying soft tissue. Although the cell‐occlusive property of GBR membranes appear to be essential to new bone formation, the role of transmembrane tissue fluid diffusion is not known. The objective of this study was to evaluate the degree to which diffusion across commonly used GBR membranes can support functional properties of osteoblast‐like cells in vitro. Cells from an established osteoblast‐like line (SAOS‐2) were cultured on membranes of cross‐linked collagen, noncross linked collagen, and ePTFE. The membranes rested on metal grids which allowed the membranes to lightly contact the surface of the culture medium. As a control, cells were directly plated and cultured in control wells. At days 7 and 21, cells were harvested by scraping the membranes or culture wells and analyzed for expression of alkaline phosphatase (ALP), core binding factor 1 (cbfa‐1), bone sialoprotein‐2 (BSP‐2), and osteocalcin (OC). Expression was determined by quantitative real‐time PCR. Glucose‐6‐phosphate dehydrogenase (G6PD) served as a reference gene. The membranes were examined by transmission light microscopy. RT‐PCR revealed up‐regulation of ALP of up to 60‐fold and of cbfa‐1 and BSP of up to threefold relative to G6PDH. Expression of OC was less then onefold. The expression profile for each of the four genes tested demonstrated small variations among cells grown on different membranes. Microscopic observations revealed remnants of undisrupted osteoblast‐like cells attached to both collagen membranes. Cell morphology and spatial arrangement indicated that vitality was maintained. Diffusion through the three membranes evaluated in this study was sufficient to support osteoblast‐like cell differentiation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Fabrication of fast responsive, thermosensitive poly(N‐isopropylacrylamide) hydrogels by using diethyl ether as precipitation agent
Authors: Xu Xiao‐Ding , Wang Bo , Wang Zong‐Chun , Cheng Si‐Xue , Zhang Xian‐Zheng , Zhuo Ren‐Xi 
Published: December 2007

AbstractAn effective strategy was developed and demonstrated to improve the properties of thermosensitive poly(N‐isopropylacrylamide) (PNIPAAm) hydrogel by using diethyl ether as a precipitation agent during the polymerization/crosslinking. Results reveal that the modified PNIPAAm hydrogels have the heterogeneous network structures and decreased LCSTs in a comparison with the normal PNIPAAm hydrogel. The modified PNIPAAm hydrogels also exhibit significantly improved sensitive properties, including fast response and stable, rapid, large magnitude oscillatory shrinking–swelling upon temperature cycles around lower critical solution temperature. In addition, fish DNA, used as a model drug, is loaded into the modified PNIPAAm hydrogels, the controlled release behaviors of the drug loaded hydrogels at different temperatures (22 and 37°C) are further examined. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Histological analysis of induced cartilage on the biodegradable or nonbiodegradable membranes from immature muscular tissue in vitro
Authors: Hayashi Tatsuhide , Kawai Tatsushi , Ishikawa Atsuko , Kawai Hideki , Nakano Kenjiro , Takei Yukiko , Kuroki Kenjiro 
Published: December 2007

AbstractSuccessful tissue engineering relies on a combination of cells, cytokines, and appropriate scaffolds. Here, we tried to induce the formation of cartilage in vitro using immature muscular tissue, crude bone morphogenetic protein (BMP) as a source of the cytokine, and biodegradable membranes (BioMend®; BM and GC‐membrane; GC‐M) or a nonbiodegradable membrane (GORE‐TEX®; GT) as scaffolds. Crude BMP was extracted from bovine cortical bones, dried, and dissolved in 1M urea before it was added to immature muscular tissue from the forelimbs of fetal Sprague Dawley rats at 20 days of pregnancy. The tissue was then cultured for 2 weeks in a carbon dioxide incubator. Complete cartilage was observed only when GT was used as a scaffold. In addition, cartilage‐like tissue formation was observed when BM was used, and partial cartilage formation was observed for GC‐M. Therefore, these results show that immature muscular tissue differentiated into cartilage and GORE‐TEX® is the most effective material for use as a scaffold in this model of tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Collagen release kinetics of surface functionalized 45S5 Bioglass®‐based porous scaffolds
Authors: Chen Q. Z. , Ahmed I. , Knowles J. C. , Nazhat S. N. , Boccaccini A. R. , Rezwan K. 
Published: December 2007

AbstractA highly interconnected porous scaffold made from 45S5 Bioglass® was fabricated by the polymer replica technique and surface functionalized for protein immobilization. Subsequently rat‐tail collagen type I was immobilized on the scaffolds. The protein and ion release rates were determined by UV–vis spectroscopy and ion chromatography, respectively, and the impact on hydroxyapatite (HA) formation on the scaffolds upon immersion in SBF was evaluated. It was discovered that the surface functionalization enhanced the stability of the collagen attachment and stability against the increment of pH in a biological environment, resulting in similar collagen release kinetics in solutions of different pH values. Without the surface modification, collagen release was considerably expedited by the increment of pH in a surrounding solution. It was also found that the collagen immobilization does not effect the formation of carbonated HA on the scaffold surface. The stable collagen attachment to the functionalized scaffold makes this approach potentially suitable for improving cell attachment and thus for enhancing the application potential of the scaffold in tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Immobilized cytokines as biomaterials for manufacturing immune cell based vaccines
Authors: Leclerc Claude , Brose Claudia , Nouzé Clémence , Leonard Fransisca , Majlessi Laleh , Becker Sybille , von Briesen Hagen , Lo‐Man Richard 
Published: December 2007

AbstractManufacturing of bioactive cell culture substrates represents a major challenge for the development of cell therapy for tissue repair and immune treatment of cancers, infectious diseases, or immunodeficiencies. In this context, we evaluated the capacity of several differentiation factors, including Granulocyte Macrophage Colony Stimulating Factor (GM‐CSF) and Macrophage Colony Stimulating Factor (M‐CSF), to drive differentiation of primary cell cultures, once immobilized on surfaces. We show that covalently immobilized signal factors fully retain their biological properties and efficiently promote differentiation of mouse and/or human precursor cells leading to the production of dendritic cells and macrophages. For GM‐CSF, we also show that the efficiency of receptor signaling is comparable using either soluble or tethered molecules. Such artificial bioactive interfaces are suitable for the development and automated production of cell‐based vaccines and therapies. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Crohn's disease and color Doppler sonography: Response to treatment and its relationship with long‐term prognosis
Authors: Ripollés Tomás , Martínez María J. , Barrachina María M. 
Published: December 2007

AbstractPurposeTo evaluate the ability of sonography to detect changes in patients undergoing treatment for Crohn's disease and whether these findings are related to the patient's long‐term outcome.MethodsTwenty‐eight patients with Crohn's disease were examined prospectively using gray‐scale and color Doppler sonography before and during treatment. Three sonographic examinations were made: on the first day of treatment, between 3 and 8 days later, and approximately 4 weeks after starting the treatment. Sonographic examination included an evaluation of maximum bowel wall thickness and vascularity pattern. The sonographic data were compared with clinical and laboratory data, and possible relation with the patient's long‐term outcome was considered.ResultsInitial baseline sonograms revealed at least 1 thickened segment of the bowel wall in all of the patients. In this initial examination, 18 of 22 patients (81%) with clinically active disease had moderate or marked parietal vascularity. A statistically significant reduction in the vascularity of the affected bowel was observed on the third sonographic examination (p < 0.05). Seventeen patients who were in clinical remission had relapses and were treated with immunosuppressive therapy or surgery during the follow‐up. Eighty‐six percent of the patients with residual hyperemia on sonographic examination after treatment had an unfavorable clinical course compared with only 30% of the patients with no, or barely visible, residual hyperemia (p < 0.01).ConclusionSonography can identify bowel inflammation and its changes during treatment. In patients with Crohn's disease, hyperemia on color Doppler sonography during clinical remission after treatment may reflect an increased risk of relapse. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Difference in migration of placenta according to the location and type of placenta previa
Authors: Cho Jeong Yeon , Lee Young‐Ho , Moon Min Hoan , Lee Jung Ha 
Published: December 2007

AbstractPurpose.To correlate the incidence and rate of placental migration with the mode of delivery, pregnancy outcome, and maternal complication according to the location (anterior versus posterior) and type of placenta previa (PP).Methods.We prospectively evaluated the placentas of 98 pregnant women with PP or low‐lying placenta (LLP) at the prenatal sonographic examination performed between 20 and 27 gestational weeks. We divided the pregnant women into groups according to type and location of PP. Follow‐up sonographic examination was performed between 32 and 37 weeks. We compared incidence of migration to the normal position and calculated the migration rate as the migrated distance divided by the weeks of interval between 2 sonographic examinations. We compared the incidences of cesarean section, fetal outcome, and maternal complications during the pregnancy.Results.The incidence of migration in the group of anterior placentas was significantly higher than that in the group of posterior placentas. The mean migration rate in the anterior group was 2.6 mm/week, whereas that in the posterior group was 1.6 mm/week. The migration rate of incomplete PP was significantly higher than that of LLP. Incidence of cesarean section for nonmigrated PP was significantly higher in the posterior group. The incidences of premature delivery and vaginal spotting were also significantly higher in the posterior group.Conclusion.Anterior PP and LLP may migrate more often and faster than posterior PP. Our results may be useful for planning of prenatal management and counseling patients with PP and LLP. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Intrathecal coelectrotransfer of a tetracycline‐inducible, three‐plasmid‐based system to achieve tightly regulated antinociceptive gene therapy for mononeuropathic rats
Authors: Chen Kuan‐Hung , Wu Chih‐Hsien , Tseng Chia‐Chih , Shiau Jieh‐Min , Lee Chien‐Te , Lin Chung‐Ren 
Published: December 2007

AbstractFor optimal use of antinociceptive gene therapy, it may be important to have extrinsic control of the expression of the transfected gene. To achieve this goal, we used a tetracycline‐inducible system (Tet‐On) composed of three plasmids coding for beta‐endorphin, the tetracycline transcriptional activator rtTA, and the silencer tTS. The regulation of beta‐endorphin expression was first assessed in cultures of dorsal root ganglion neurons. The three plasmids were then electrotransfected into the spinal cord of mononeuropathic rats and the analgesic potential of this therapy in vivo was evaluated by thermal‐withdrawal latency and the mechanical‐withdrawal threshold. Intraperitoneal injections of doxycycline were made to evaluate the possibility of exogenous upregulation of transfected beta‐endorphin gene expression in vivo. The levels of beta‐endorphin were analyzed by intrathecal microdialysis and radioimmunoassay. We found that, after doxycycline administration, the expression of beta‐endorphin was rapid, stable, and tightly regulated (low background and high induction level) both in vitro and in vivo. The beta‐endorphin protein was secreted into cerebrospinal fluid at a peak level of 53 pmol/L in dialysate, which was sufficient to inhibit neuropathic pain. In conclusion, tightly controlled expression of beta‐endorphin can be obtained following intrathecal electrotransfer of a tetracycline‐inducible, three‐plasmid‐based system, and doxycycline‐dependent beta‐endorphin protein expression in this system alleviates sciatic nerve constriction‐induced limb pain. Copyright © 2007 John Wiley & Sons, Ltd.
Echo combination to reduce proton resonance frequency (PRF) thermometry errors from fat
Authors: Rieke Viola , Butts Pauly Kim 
Published: December 2007

AbstractPurposeTo validate echo combination as a means to reduce errors caused by fat in temperature measurements with the proton resonance frequency (PRF) shift method.Materials and MethodsComputer simulations were performed to study the behavior of temperature measurement errors introduced by fat as a function of echo time. Error reduction by combining temperature images acquired at different echo times was investigated. For experimental verification, three echoes were acquired in a refocused gradient echo acquisition. Temperature images were reconstructed with the PRF shift method for the three echoes and then combined in a weighted average. Temperature measurement errors in the combined image and the individual echoes were compared for pure water and different fractions of fat in a computer simulation and for a phantom containing a homogenous mixture with 20% fat in an MR experiment.ResultsIn both simulation and MR measurement, the presence of fat caused severe temperature underestimation or overestimation in the individual echoes. The errors were substantially reduced after echo combination. Residual errors were about 0.3°C for 10% fat and 1°C for 20% fat.ConclusionEcho combination substantially reduces temperature measurement errors caused by small fractions of fat. This technique then eliminates the need for fat suppression in tissues such as the liver. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.