bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transplantation of immortalized mesencephalic progenitors (CSM14.1 cells) into the neonatal parkinsonian rat caudate putamen
Authors: Haas Stefan Jean‐Pierre , Beckmann Stephan , Petrov Stanislav , Andressen Christian , Wree Andreas , Schmitt Oliver 
Published: January 2007

AbstractThe present study analyzed whether grafts of the mesencephalic progenitor cell line CSM14.1 into the neonatal rat caudate putamen (CPu) differentiate into neurons and whether this is accompanied by a functional improvement in 6‐hydroxydopamine (6‐OHDA)‐lesioned animals. As in previous studies, a neuronal differentiation of CSM14.1 cells transplanted into the CPu of adult animals could not be observed, so we here used neonatal rats, because graft location and host age seemingly are crucial parameters for neural transplant differentiation and integration. Rats bilaterally lesioned at postnatal day 1 by intraventricular 6‐OHDA‐injections 2 days later received 100,000 CSM14.1 cells prelabelled with the fluorescent dye PKH26 into the right CPu. Five weeks after grafting, the cylinder test was performed, and the data compared with data from age‐matched intact controls and bilaterally lesioned‐only animals. Brain slices immunostained for tyrosine hydroxylase (TH) were quantified by optical densitometry. We observed a significant preference of left forelimb use exclusively in transplanted animals. In these rats, TH‐containing perikarya were found in the grafted CPu, presumedly leading to the significant increase of TH‐immunoreactive fibers in this region. Moreover, confocal laser microscopy revealed a differentiation of transplanted PKH26‐labelled CSM14.1 cells into neuronal nuclei antigen or TH‐immunoreactive cells. Thus, CSM14.1 cells differentiate into TH‐containing neurons, which most probably contribute to the preferred forelimb use, indicating a functional integration of CSM14.1 cells into the host basal ganglia loops during early postnatal development. These findings that are in contrast to observations in adult rats suggest instructive cues for neuronal differentiation and integration given by the neonatal microenvironment. © 2007 Wiley‐Liss, Inc.
Standardized T2* map of normal human heart in vivo to correct T2* segmental artefacts
Authors: Positano Vincenzo , Pepe Alessia , Santarelli Maria Filomena , Scattini Barbara , De Marchi Daniele , Ramazzotti Anna , Forni Gianluca , Borgna‐Pignatti Caterina , Lai Maria Eliana , Midiri Massimo , Maggio Aurelio , Lombardi Massimo , Landini Luigi 
Published: January 2007

AbstractA segmental, multislice, multi‐echo T2* MRI approach could be useful in heart iron‐overloaded patients to account for heterogeneous iron distribution, demonstrated by histological studies. However, segmental T2* assessment in heart can be affected by the presence of geometrical and susceptibility artefacts, which can act on different segments in different ways. The aim of this study was to assess T2* value distribution in the left ventricle and to develop a correction procedure to compensate for artefactual variations in segmental analysis. MRI was performed in four groups of 22 subjects each: healthy subjects (I), controls (II) (thalassemia intermedia patients without iron overload), thalassemia major patients with mild (III) and heavy (IV) iron overload. Three short‐axis views (basal, median, and apical) of the left ventricle were obtained and analyzed using custom‐written, previously validated software. The myocardium was automatically segmented into a 16‐segment standardized heart model, and the mean T2* value for each segment was calculated. Punctual distribution of T2* over the myocardium was assessed, and T2* inhomogeneity maps for the three slices were obtained. In group I, no significant variation in the mean T2* among slices was found. T2* showed a characteristic circumferential variation in all three slices. The effect of susceptibility differences induced by cardiac veins was evident, together with low‐scale variations induced by geometrical artefacts. Using the mean segmental deviations as correction factors, an artefact correction map was developed and used to normalize segmental data. The correction procedure was validated on group II. Group IV showed no significant presence of segmental artefacts, confirming the hypothesis that susceptibility artefacts are additive in nature and become negligible for high levels of iron overload. Group III showed a greater variability with respect to normal subjects. The correction map failed to compensate for these variations if both additive and percentage‐based corrections were applied. This may reinforce the hypothesis that true inhomogeneity in iron deposition exists. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of extracellular proteins produced by Aeromonas hydrophila AH‐1
Authors: Yu Hong Bing , Kaur Rasvinder , Lim Simin , Wang Xian Hui , Leung Ka Yin 
Published: January 2007

AbstractAeromonas hydrophila is a ubiquitous Gram‐negative bacterium which can cause motile aeromonad septicemia in both fish and humans. A. hydrophila secretes many extracellular proteins associated with pathogenicity and environmental adaptability. In this study, an extracellular proteome map of A. hydrophila AH‐1 was constructed. The major extracellular virulence factors were characterized by comparing the proteomes of various deletion mutants with that of the wild type. The results suggested that serine protease was involved in the processing of a toxin and secreted enzymes such as hemolysin, glycerophospholipid‐cholesterol acyltransferase and metalloprotease. We also showed that expressions of polar and lateral flagellins were under the control of temperature, FlhA, LafK, and RpoN. In addition, three novel proteins (potential effector proteins including one ExoT‐like protein) were revealed to be secreted via the type III secretion system (TTSS) of A. hydrophila AH‐1. Another novel finding was the demonstration of a crosstalk between the lateral flagellar system and the TTSS in A. hydrophila. These results showed that proteomics is a powerful tool for characterizing virulence factors. The construction of proteome maps will provide a valuable means of finding potential candidates for developing suitable diagnostics and therapeutics for this emerging pathogen.
Fundamentals and development of high‐efficiency supported catalyst systems for atom transfer radical polymerization
Authors: Faucher Santiago , Zhu Shiping 
Published: January 2007

AbstractAtom transfer radical polymerization (ATRP) is a controlled/living radical polymerization process developed a decade ago that allows the synthesis of tailored macromolecules. It has been widely used in the laboratory for polymer synthesis since but little use has been made of it at the industrial scale for polymer production. This is due to the low activity of the ATRP catalyst that is central to the process. Much work has been done over the years to overcome this challenge, and the greatest successes have been achieved through catalyst supporting and recycling. We present here a historical account of the development of supported ATRP catalysts while shedding light on their present and future challenges. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 553–565, 2007
AB and ABA type butyl acrylate and styrene block copolymers via RAFT‐mediated miniemulsion polymerization
Authors: Bowes A. , Mcleary J. B. , Sanderson R. D. 
Published: January 2007

AbstractTwo trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agents are compared in miniemulsion polymerization of styrene and butyl acrylate and the formation of seeded emulsion block copolymers. The order of block synthesis and the number of block segments per polymer are discussed. The use of nonionic surfactants is examined and the type of surfactant in relation to the monomer used is found to have a significant affect on latex formation. Conditions are shown by which AB and ABA type block copolymers can be successfully prepared via a seeded RAFT‐mediated emulsion polymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 588–604, 2007
Effects of active‐learning experiences on achievement, attitudes, and behaviors in high school biology
Authors: Taraban Roman , Box Cathy , Myers Russell , Pollard Robin , Bowen Craig W. 
Published: January 2007

AbstractActive‐learning labs for two topics in high school biology were developed through the collaboration of high school teachers and university faculty and staff and were administered to 408 high school students in six classrooms. The content of instruction and testing was guided by State of Texas science objectives. Detailed teacher records describing daily classroom activities were used to operationalize two types of instruction: active learning, which used the labs; and traditional, which used the teaching resources ordinarily available to the teacher. Teacher records indicated that they used less independent work and fewer worksheets, and more collaborative and lab‐based activities, with active‐learning labs compared to traditional instruction. In‐class test data show that students gained significantly more content knowledge and knowledge of process skills using the labs compared to traditional instruction. Questionnaire data revealed that students perceived greater learning gains after completing the labs compared to covering the same content through traditional methods. An independent questionnaire administered to a larger sample of teachers who used the lab‐based curriculum indicated that they perceived changing their behaviors as intended by the student‐centered principles of the labs. The major implication of this study is that active‐learning–based laboratory units designed and developed collaboratively by high school teachers and university faculty, and then used by high school teachers in their classrooms, can lead to increased use of student‐centered instructional practices as well as enhanced content knowledge and process learning for students. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 960–979, 2007
Oxidation of N‐methyl‐γ‐tocopheramine to a nitroxide
Authors: Murphy Patricia A. , Lin James S. , Olcott Harold S. , Windle John J. 
Published: January 2007

AbstractAn unstable nitroxide identified by electron paramagnetic resonance spectra was obtained by oxidation of N‐methyl‐γ‐tocopheramine with peroxide and also by ultraviolet photooxidation.
Glyceroamidothiophosphates of cholecalciferol (Vitamin D3)
Authors: Stamatov Stephan D. , Gronowitz Salo 
Published: January 2007

AbstractThe hexamethyltriamide of phosphorous acid activated by the addition of iodine at the optimum molar ratio 1.05∶0.05 was used as a phosphorylating reagent to synthesize cholecalciferyl‐3‐0‐(N,N‐dimethylamido)thiophosphate derivatives of 1,3‐benzylidene‐rac‐glycerol, 1,2‐isopropylidene‐rac‐glycerol, 1,3‐dioleoyl‐rac‐glycerol, and 1,2‐dioleoyl‐rac‐glycerol in a one‐pot procedure in high overall yields (81–86%). The compounds represent new model types of phospholipid structures which, in addition to glycerol and a steroid fragment, contain a biologically important linkage other than an oxygen‐phosphorus bond.
Ingestion of high doses of fish oil increases the susceptibility of cellular membranes to the induction of oxidative stress
Authors: Garrido Argelia , Garrido Fernando , Guerra Ricardo , Valenzuela Alfonso 
Published: January 2007

AbstractFeeding rats with 4 g/kg body weight of sardine oil during 7 or 14 days increases the content of eicosapentaenoic acid and docosahexanoic acid in the erythrocyte and hepatic microsomal membranes by 2 to 6%. These membranes show increased susceptibility to the induction of oxidative stress, expressed as lipid peroxidation, when they are exposed to Fe2+‐ascorbate and to NADPH‐Fe3+‐ADP, respectively. The results indicate that in order to prevent the increased susceptibility to lipid peroxidation, supplementation with larger amounts of antioxidants may be needed than those required to stabilize the oil.
Fluorescent products of lipid peroxidation: I. Structural requirement for fluorescence in conjugated schiff bases
Authors: Malshet V. G. , Al Tappel L. 
Published: January 2007

AbstractThe structural requirement for fluorescence in Schiff bases was defined. Aldehydes and amines were reacted and the structures of the Schiff bases N‐hydroxyethyl‐1‐imino‐2′,4′‐hexadiene (I), N‐1‐benzal‐2‐hydroxyaminoethane (II), and N‐1‐benzal‐2,2′‐hydroxyaminoethane (III) were established by elemental analysis, IR spectral analysis and mass spectral analysis. The structures of N‐alanyl‐2‐hydroxy‐naphthylidine (IV) and N,N′‐dileucinyl‐1‐amino‐3‐iminopropene (V) had been established previously. III, IV and V were fluorescent compounds and I and II were not. The results of these analyses suggest that an electron donating group in conjugation with an imine is the structure required for fluorescence.
Avian blood parasites in an endangered columbid:Leucocytozoon marchouxiin the Mauritian Pink PigeonColumba mayeri
Authors: BUNBURY N. , BARTON E. , JONES C. G. , GREENWOOD A. G. , TYLER K. M. , BELL D. J. 
Published: January 2007

SUMMARYThere is increasing evidence that pathogens can play a significant role in species decline. This study of a complete free-living species reveals a cost of blood parasitism to an endangered host, the Pink PigeonColumba mayeri, endemic to Mauritius. We investigated the prevalence and effect of infection of the blood parasite,Leucocytozoon marchouxi, in the free-living Pink Pigeon population. Overall,L. marchouxiinfection prevalence detected was 18·3%. Juveniles were more likely to be infected than older birds and there was geographical variation in infection prevalence. Survival of birds infected withL. marchouxiwas lower than that of uninfected birds to 90 days post-sampling. This study suggests that while common haematozoa are well tolerated in healthy adults, these parasites may have greater pathogenic potential in susceptible juveniles. The study is unusual given its completeness of species sampling (96%) within a short time-period, the accurate host age data, and its focus on blood parasites in a threatened bird species. Species for which long-term life-history data are available for every individual serve as valuable models for dissecting the contribution of particular pathogens to species decline.
Using Statistical Analysis for Setting Process Validation Acceptance Criteria for Biotech Products
Authors: Wang Xiangyang , Germansderfer Abe , Harms Jean , Rathore Anurag S. 
Published: January 2007

AbstractThis paper discusses the challenges of setting process validation acceptance criteria for biotech products for cases where using statistical tools is appropriate. Data are analyzed under three different scenarios that are frequently encountered in biotech applications. Scenario A represents the case when a small data set around center point conditions is available for setting acceptance criteria. Scenario B represents the case when a larger data set within normal operation conditions is available for setting acceptance criteria. Scenario C represents the case when a large characterization data set is available for setting acceptance criteria and it is possible to accurately model the impact of operation conditions on performance of the step. Statistical approaches including mean ± 3SD, tolerance interval analysis, prediction profiler, and Monte Carlo simulation are applied to the different scenarios. Strengths and shortcomings of the different statistical tools are discussed, and the best approach for each scenario is recommended. It is shown that selection of the right statistical approach is a critical first step toward setting appropriate acceptance criteria.
Application of Multivariate Analysis toward Biotech Processes: Case Study of a Cell‐Culture Unit Operation
Authors: Kirdar Alime Ozlem , Conner Jeremy S. , Baclaski Jeffrey , Rathore Anurag S. 
Published: January 2007

AbstractThis paper examines the feasibility of using multivariate data analysis (MVDA) for supporting some of the key activities that are required for successful manufacturing of biopharmaceutical products. These activities include scale‐up, process comparability, process characterization, and fault diagnosis. Multivariate data analysis and modeling were performed using representative data from small‐scale (2 L) and large‐scale (2000 L) batches of a cell‐culture process. Several input parameters (pCO2, pO2, glucose, pH, lactate, ammonium ions) and output parameters (purity, viable cell density, viability, osmolality) were evaluated in this analysis. Score plots, loadings plots, and VIP plots were utilized for assessing scale‐up and comparability of the cell‐culture process. Batch control charts were found to be useful for fault diagnosis during routine manufacturing. Finally, observations made from reviewing VIP plots were found to be in agreement with conclusions from process characterization studies demonstrating the effectiveness of MVDA as a tool for extracting process knowledge.
Modulation of drug-stimulated ATPase activity of human MDR1/P-glycoprotein by cholesterol
Authors: Kimura Yasuhisa , Kioka Noriyuki , Kato Hiroaki , Matsuo Michinori , Ueda Kazumitsu 
Published: January 2007

MDR1 (multidrug resistance 1)/P-glycoprotein is an ATP-driven transporter which excretes a wide variety of structurally unrelated hydrophobic compounds from cells. It is suggested that drugs bind to MDR1 directly from the lipid bilayer and that cholesterol in the bilayer also interacts with MDR1. However, the effects of cholesterol on drug–MDR1 interactions are still unclear. To examine these effects, human MDR1 was expressed in insect cells and purified. The purified MDR1 protein was reconstituted in proteoliposomes containing various concentrations of cholesterol and enzymatic parameters of drug-stimulated ATPase were compared. Cholesterol directly binds to purified MDR1 in a detergent soluble form and the effects of cholesterol on drug-stimulated ATPase activity differ from one drug to another. The effects of cholesterol on Km values of drug-stimulated ATPase activity were strongly correlated with the molecular mass of that drug. Cholesterol increases the binding affinity of small drugs (molecular mass &lt;500 Da), but does not affect that of drugs with a molecular mass of between 800 and 900 Da, and suppresses that of valinomycin (molecular mass &gt;1000 Da). Vmax values for rhodamine B and paclitaxel are also increased by cholesterol, suggesting that cholesterol affects turnover as well as drug binding. Paclitaxel-stimulated ATPase activity of MDR1 is enhanced in the presence of stigmasterol, sitosterol and campesterol, as well as cholesterol, but not ergosterol. These results suggest that the drug-binding site of MDR1 may best fit drugs with a molecular mass of between 800 and 900 Da, and that cholesterol may support the recognition of smaller drugs by adjusting the drug-binding site and play an important role in the function of MDR1.
Two metallocarboxypeptidases from the protozoan Trypanosoma cruzi belong to the M32 family, found so far only in prokaryotes
Authors: Niemirowicz Gabriela , Parussini Fabiola , Agüero Fernán , Cazzulo Juan J. 
Published: January 2007

MCPs (metallocarboxypeptidases) of the M32 family of peptidases have been identified in a number of prokaryotic organisms, and only a few of them have been characterized biochemically. Members of this family are absent from eukaryotic genomes, with the remarkable exception of those of trypanosomatids. The genome of the CL Brener clone of Trypanosoma cruzi, the causative agent of Chagas' disease, encodes two such MCPs, with 64% identity between them: TcMCP-1 and TcMCP-2. Both genes, which are present in a single copy per haploid genome, were expressed in Escherichia coli as catalytically active polyHis-tagged recombinant enzymes. Despite their identity, the purified TcMCPs displayed marked biochemical differences. TcMCP-1 acted optimally at pH 6.2 on FA {N-(3-[2-furyl]acryloyl)}-Ala-Lys with a Km of 166 μM. Activity against benzyloxycarbonyl-Ala-Xaa substrates revealed a P1′ preference for basic C-terminal residues. In contrast, TcMCP-2 preferred aromatic and aliphatic residues at this position. The Km value for FA-Phe-Phe at pH 7.6 was 24 μM. Therefore the specificities of both MCPs are complementary. Western blot analysis revealed a different pattern of expression for both enzymes: whereas TcMCP-1 is present in all life cycle stages of T. cruzi, TcMCP-2 is mainly expressed in the stages that occur in the invertebrate host. Indirect immunofluorescence experiments suggest that both proteins are localized in the parasite cytosol. Members of this family have been identified in other trypanosomatids, which so far are the only group of eukaryotes encoding M32 MCPs. This fact makes these enzymes an attractive potential target for drug development against these organisms.
Eukaryotic ternary transcription complexes: transcription complexes of RNA polymerase II are associated with histone-containing, nucleosome-like particles in vivo
Authors: Sargan David R. , Butterworth Peter H.W. 
Published: January 2007

Abstract
Using a psoralen crosslinking, radioactive labelling technique, we have previously been able to study ternary transcription complexes containing DNA-dependent RNA polymerases I and II which are released from rat liver nuclei by endogenous nuclease digestion [Sargan and Butterworth, refs 1 and 2]. Although the DNA component of these complexes was found to have a ‘nucleosome-Uke’ size profile and although the experimental conditions for autodigestion were designed to minimise histone rearrangement, 1t is necessary to provide further evidence that the periodicity of nuclease cutting around these transcription complexes 1s conferred by histones. Studies using secondary nuclease digestion of the released transcription complexes now show a digestion barrier characteristic of that conferred by nucleosomal histones which is lost if histones are removed from the complexes. Furthermore, antibodies raised against histones are effective in precipitating transcription complexes of RNA polymerase II and, to a lesser extent, of RNA polymerase I. The data suggest that, in rat hepatic tissue, transcription complexes are in very close proximity (within a few hundred base pairs) of histone-containing, nucleosome-like particles in vivo
Fidelity of DNA synthesis by the Thermococcus litoralis DNA polymerase—an extremely heat stable enzyme with proofreading activity
Authors: Mattila P. , Korpela J. , Tenkanen T. , Pitkämem K. 
Published: January 2007

Abstract
We demonstrate that the DNA polymerase isolated from Thermococcus litoralis (VentTM DNA polymerase) is the first thermostable DNA polymerase reported having a 3′—5′ proofreading exonuclease activity. This facilitates a highly accurate DNA synthesis in vitro by the polymerase. Mutational frequencies observed in the base substitution fidelity assays were in the range of 30×10−6. These values were 5–10 times lower compared to other thermostable DNA polymerases lacking the proofreading activity. All classes of DNA polymerase errors (transitions, transversions, frameshift mutations) were assayed using the forward mutational assay (1). The mutation frequencies of Thermococcus litoralis DNA polymerase varied between 15−35×10−4 being 2 – 4 times lower than the respective values obtained using enzymes without proofreading activity. We also noticed that the fidelity of the DNA polymerase from Thermococcus litoralis responds to changes in dNTP concentration, units of enzyme used per one reaction and the concentration of MgSO4 relative to the total concentration of dNTPs present in the reaction. The high fidelity DNA synthesis In vitro by Thermococcus litoralis DNA polymerase provides good possibilities for maintaining the genetic information of original target DNA sequences intact in the DNA amplification applications.