bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen bonding, solvation, and hydrolysis of cisplatin: A theoretical study
Authors: Robertazzi Arturo , Platts James A. 
Published: March 2004

AbstractDensity functional calculations on a range of hydrogen bonded clusters of cisplatin are reported. A systematic search of 1:1 cisplatin:water complexes reveals only three stable minima, which contain a number of common, recurring interactions, such as an NH … OH … Cl bridging mode. Expanding these clusters by adding water molecules leads to a model of the first solvation shell of cisplatin, which contains the above motifs along with several strong waterwater interactions. The strengths of such interactions are rationalized on the basis of electrostatic potentials, and quantified by use of Atoms in Molecules properties. This analysis also allows us to estimate cisplatin's position on Abraham's hydrogen bond acidity and basicity scales, indicating that cisplatin is a strong donor and acceptor of hydrogen bonds due to the dominance of hard, electrostatic interactions. The effects of this explicit solvation on the barrier to hydrolysis, and hence activation, of cisplatin are explored, indicating a slightly higher barrier than in the gas phase, leading to better agreement with experiment than either gas phase or continuum solvation calculations. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1060–1067, 2004
Gene delivery to respiratory epithelial cells by magnetofection
Authors: Gersting Soeren W. , Schillinger Ulrike , Lausier James , Nicklaus Petra , Rudolph Carsten , Plank Christian , Reinhardt Dietrich , Rosenecker Joseph 
Published: March 2004

AbstractBackgroundFor the topical application of DNA vector complexes to the airways, specific extracellular barriers play a major role. In particular, short contact time of complexes with the cell surface caused by the mucociliary clearance hinders cellular uptake of complexes. The aim of this study was to evaluate the ability of magnetofection, a technique based on the principle of magnetic drug targeting, to overcome these barriers in comparison with conventional nonviral gene transfer methods such as lipofection and polyfection.MethodsExperiments were carried out on permanent (16HBE14o‐) and primary airway epithelial cells (porcine and human), and native porcine airway epithelium ex vivo. Transfection efficiency and dose‐response relationship of magnetofection were examined by luciferase reporter gene expression. Sedimentation patterns and uptake of gene transfer complexes were characterized by fluorescence and electron microscopy, respectively.ResultsWe show that (i) application of a magnetic field allows the magnetofectins to sediment and to enrich at the cell surface within a few minutes, (ii) magnetofection bears an improved dose‐response relationship, (iii) magnetofection enhances transfection efficiency in both, permanent and primary airway epithelial cells, and (iv) magnetofection leads to significant transgene expression at very short incubation times in an ex vivo airway epithelium organ model.ConclusionsMagnetofection provides a potential novel method, which may overcome fundamental limitations of nonviral gene transfer to the airways. Due to the accelerated enrichment at the cell surface it may be of major interest for in vivo applications, where long‐term incubation times at the target tissue are hardly achievable. Copyright © 2004 John Wiley & Sons, Ltd.
The role of dextran conjugation in transfection mediated by dextran‐grafted polyethylenimine
Authors: Tseng Wen‐Chi , Tang Chien‐Hsiang , Fang Tsuei‐Yun 
Published: March 2004

AbstractBackgroundConjugation through primary amines is one of the most commonly used methods to modify polycationic vectors for gene delivery. A better understanding of the effect of the conjugation on the mechanisms of transgene expression can help design efficient polycationic vectors.MethodsDextran with a molecular weight of 1500 was grafted onto polyethylenimine (PEI) to produce various degrees of grafting in an effort to investigate how the conjugation affected the mechanisms of transgene expression. Flow cytometry was employed to quantitate the cellular entry of plasmid and the level of transgene expression, which were measured using ethidium monoazide labeled plasmid and green fluorescent protein (GFP), respectively. The buffering capacity of the grafted PEI was determined by titration, and the integrity of the DNA‐polymer complexes were examined by exposure to heparin.ResultsGrafting of dextran onto PEI was found to significantly diminish the cytotoxicity, buffering capacity, cellular entry, and the integrity of the DNA‐polymer complexes. The reductions enlarged as the degree of grafting increased from 0 to 1.84%; however, at an optimal degree of grafting, the dextran‐grafted PEI enhanced the percentages of GFP‐positive cells to a level 3 times and 1.3 times of those mediated by unmodified PEI for CHO and MDA‐MB‐231 cells, respectively.ConclusionsThese results demonstrated that the conjugation of dextran onto the primary amines of PEI inhibited the entry of plasmid across the cell membrane, but the change in the structures of the DNA‐polymer complexes was able to promote transgene expression when the degrees of conjugation fell below 0.64%. Copyright © 2004 John Wiley & Sons, Ltd.
Vesicular stomatitis virus glycoprotein: a transducing coat for SFV‐based RNA vectors
Authors: Dorange Fabien , Piver Eric , Bru Thierry , Collin Christine , Roingeard Philippe , Pagès Jean‐Christophe 
Published: March 2004

AbstractBackgroundSemliki Forest virus (SFV) vectors have a great potential for the induction of protective immunity in a large number of clinical conditions including cancer. Such a potential accounts for the huge efforts made to improve the in vivo expression from SFV vectors. It is noteworthy that efficient in vivo expression strongly relies on the ability to deliver high‐titre vectors. To achieve this, the generation of recombinant SFV particles, using independent expression systems for structural SFV genes, has been proposed. However, despite several modifications in the production process, a risk of contamination with replication‐competent, or partially recombined, virus has remained.MethodsHere, we exploit the ability of the vesicular stomatitis virus glycoprotein (VSV‐G), expressed in trans, to hijack full‐length genomic SFV RNA into secreted virus‐like particles (VLPs). To allow SFV vector mobilisation, we designed a CMV driven SFV vector in which the internal 26S promoter has been extensively mutated. With this vector, mobilisation events were monitored using the Green Fluorescent Protein (GFP). The production procedure involves a sequential transfection protocol, of plasmids expressing the VSV‐G and the SFV vector respectively.ResultsWe show that the VLPs are effective for cellular delivery of SFV vectors in a broad range of human and non‐human cellular targets. Furthermore, production of VLPs is easy and allows, through concentration, the harvest of high‐titre vector.ConclusionsThe present paper describes a convenient process aimed at mobilising full length SFV vectors. A major issue to consider, while developing clinically relevant gene transfer vectors, is the risk of undesirable generation of replication competent by‐products. Importantly, as the VSV‐G gene shares no homology with the SFV genome, our VLPs offer a strong guarantee of biosafety. Copyright © 2004 John Wiley & Sons, Ltd.
Improved non‐viral transfection of glial and adult neural stem cell lines and of primary astrocytes by combining agents with complementary modes of action
Authors: Tinsley Rogan B. , Vesey Melanie J. , Barati Shahram , Rush Robert A. , Ferguson Ian A. 
Published: March 2004

AbstractBackgroundRational design of gene vectors for therapeutic applications requires understanding of transfection mechanisms. In this study, multiple transfection assays revealed complementary mechanisms between two commonly used transfection agents. This finding was then exploited to produce improved transfection outcomes.Methods and resultsRat C6 glial cells, adult rat hippocampal progenitor cells and primary astrocytes were transfected using Lipofectamine (LA) or polyethylenimine (PEI), in vitro. Although LA‐ and PEI‐transfected populations expressed the same total level of transgene product, LA transfected considerably more cells than PEI (approximately 20 vs. 14%). A fluorescently labelled plasmid and time‐course analysis, involving both flow cytometry and confocal microscopy, were used to explain this apparent discrepancy. Results showed that LA delivered more plasmid DNA to the cytoplasm and achieved transgene expression in more cells than PEI. In contrast, PEI transfected fewer cells but, on average, produced more transgene product per transfected cell.ConclusionsA comparative transfection model was developed to explain these different characteristics. According to this model, transfection is a multistage process with different transfection agents exerting their primary effect at different stages in this process. This model forecast that it should be possible to prepare a chimeric complex with a transfection efficiency that exceeded that achievable with Lipofectamine or polyethylenimine alone. This prediction was tested and shown to hold for glioma cells, primary astrocytes, and adult neural stems cells. Copyright © 2004 John Wiley & Sons, Ltd.
Adenoviral‐mediated HGF expression inhibits germ cell apoptosis in rats with cryptorchidism
Authors: Goda Kazumasa , Fujisawa Masato , Shirakawa Toshiro , Dobashi Masaki , Shiota Goshi , Zhang Zhu Jun , Gotoh Akinobu , Kamidono Sadao 
Published: March 2004

AbstractBackgroundPrior studies have shown that the hepatocyte growth factor (HGF), as known for its multiple biological effects, possibly regulates spermatogenesis or tubulogenesis in the testis. To clarify the effect of HGF on restoration of spermatogenesis, or testicular weight, we transferred the HGF gene into the testis of the rat experimental cryptorchid model.MethodsReplication‐deficient recombinant adenoviral vectors containing the CAG promoter driving rat HGF (pAxCAHGF) and LacZ (pAxCALacZ) were constructed. Sprague‐Dawley rats surgically induced with unilateral cryptorchidism and subsequent orchidopexy were divided into three groups: control (PBS), pAxCALacZ and pAxCAHGF by intratesticular injection. At 2 and 4 weeks after subsequent orchidopexy, testes were removed and weighed. These specimens were analyzed histopathologically, and examined for cell apoptosis. HGF expression in these specimens associated with c‐Met receptor‐mediated signal molecules was examined by reverse transcription‐polymerase chain reaction (RT‐PCR), Western blot or immunohistochemical study.ResultsAdenovirus‐mediated HGF gene transfer induced overexpression of HGF in some seminiferous epithelial cells and interstitial cells, increased the phosphorylation of ERK and Akt, and decreased numbers of apoptotic cells of germ cells. HGF transduction also significantly increased the numbers of germ cells and testicular weight by 4 weeks compared with the other control groups.ConclusionsAdenoviral‐mediated HGF gene transfer into the testis in the cryptorchidism rats inhibited germ cell apoptosis and restored spermatogenesis. Copyright © 2004 John Wiley & Sons, Ltd.
Marked inhibition of retinal neovascularization in rats following soluble‐flt‐1 gene transfer
Authors: Rota Rossella , Riccioni Teresa , Zaccarini Marco , Lamartina Stefania , Gallo Anna Del , Fusco Angelo , Kovesdi Imre , Balestrazzi Emilio , Abeni Damiano C. , Ali Robin R. , Capogrossi Maurizio C. 
Published: March 2004

AbstractBackgroundIn mouse models of retinopathy of prematurity (ROP) inhibitors of vascular endothelial growth factor (VEGF) functions administered systemically completely block retinal neovascularization. In contrast, selective ocular VEGF depletion has achieved an approx. 50% inhibition of retinal neovascular growth. It is unclear whether a more complete inhibition of new blood vessel development can be obtained with an anti‐VEGF therapy localized to the eye. Therefore, the objective of the present study was to determine the effect of local anti‐VEGF therapy in a different animal model which closely mimics human ROP.MethodsRats were exposed to alternating cycles of high and low levels of oxygen for 14 days immediately after birth; thereafter, they were intravitreally injected with an adenoviral vector expressing a secreted form of the VEGF receptor flt‐1 (Ad.sflt), which acts by sequestering VEGF. Contralateral eyes were injected with the control vector carrying the reporter gene expressing β‐galactosidase (Ad.βGal).ResultsAt the peak of retinal neovascular growth, i.e. post‐natal day 21 (P21), we observed up to 97.5% decrease in retinal neovascularization in animals injected with Ad.sflt. At the end of observation (P28), no significant difference in retinal vessel number was detected in both oxygen‐injured and normoxic Ad.sflt‐treated retinas compared with untreated or Ad.βGal‐treated retinas.ConclusionAdenoviral‐mediated sflt‐1 gene transfer induces a near‐complete inhibition of ischemia‐induced retinal neovascularization in rats without affecting pre‐existing retinal vessels. Copyright © 2004 John Wiley & Sons, Ltd.
Introduction
Authors: Chowdhury Mushtaque , Mosley Paul , Simanowitz Anton 
Published: March 2004

AbstractAnalysis of the poverty impacts of microfinance is almost exclusively focused on the direct impacts on microfinance clients. The Imp‐Act programme emphasizes the need to also consider the ‘wider impacts’ achieved through non‐client beneficiaries of microfinance. To fully understand and achieve the social impacts to which microfinance aspires wider impacts need to be assessed and programmes designed to achieve these outcomes. This volume introduces methodologies, in most cases developed by practitioners, which measure these wider or ‘social’ impacts and use the results as a point of departure for understanding what institutional and policy interventions are required to make them more pro‐poor. The principal wider impacts discussed are health, community governance, postwar reconstruction, labour and finance markets and, in relation to Bolivia and Indonesia, the economy as a whole. We represent research into such wider impacts as a public good which is beneficial for all microfinance institutions (MFIs)—in particular for their public relations—and for the poverty impact of the sector as a whole, but which the individual institutions typically do not have the resources to assess. This indicates a clear role for donors. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of microfinance institutions in local financial markets: a case study from Kenya
Authors: Johnson Susan 
Published: March 2004

AbstractThis paper looks beyond the direct impact of microcredit provision on users to examine whether microfinance institutions (MFIs) have had wider impacts within the local financial markets in which they are operating. It considers the potential for both competition and demonstration effects on other financial providers. In the context of local financial markets in and around the small town of Karatina in Central Kenya, supply side information is used to investigate the key changes in provision between 1999 and 2003. The paper concludes that changing macroeconomic conditions have been the main driver increasing competition for middle and lower income clients and that few competition or demonstration effects resulting from the MFIs are in evidence. Copyright © 2004 John Wiley & Sons, Ltd.
Screening for control genes in rat global cerebral ischemia using high‐density oligonucleotide array
Authors: Kobayashi Megumi Sugahara , Takahashi Yasuo , Nagata Toshihito , Nishida Yayoi , Murata Akiko , Ishikawa Koichi , Asai Satoshi 
Published: March 2004

AbstractFrom conventional relative gene expression analyses (Northern blotting, in situ hybridization, and RT‐PCR), it has been reported that the expression of control genes, such as glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and β‐actin, used as references may be affected by ischemia. Therefore, we extended searching and evaluation at the mRNA level of transcripts whose expression levels were not changed by cerebral ischemia, using a high‐density oligonucleotide array and statistical analysis in a rat global cerebral ischemia and reperfusion model. We added a hyperthermic factor and localization factor to ischemia and identified transcripts with a stable expression level under conditions even more disadvantageous than ischemia only. Screening of more than 8,000 transcripts with the Rat Genome U34A array yielded 28 transcripts, which we listed and classified according to their expression level. Widely used control genes, GAPDH and β‐actin, were not included, although cyclophilin A was included. In addition, we conducted a functional classification based on gene ontology. Under the functional classification of the 28 transcripts, many genes tended to be associated with metabolism. In conclusion, use of several transcripts is recommended, such as those we identified, as references in the analysis of gene expression in pathological models of ischemia. © 2004 Wiley‐Liss, Inc.
Job demands, job resources, and their relationship with burnout and engagement: a multi‐sample study
Authors: Schaufeli Wilmar B. , Bakker Arnold B. 
Published: March 2004

AbstractThis study focuses on burnout and its positive antipode—engagement. A model is tested in which burnout and engagement have different predictors and different possible consequences. Structural equation modeling was used to simultaneously analyze data from four independent occupational samples (total N = 1698). Results confirm the hypothesized model indicating that: (1) burnout and engagement are negatively related, sharing between 10 per cent and 25 per cent of their variances; (2) burnout is mainly predicted by job demands but also by lack of job resources, whereas engagement is exclusively predicted by available job resources; (3) burnout is related to health problems as well as to turnover intention, whereas engagement is related only to the latter; (4) burnout mediates the relationship between job demands and health problems, whereas engagement mediates the relationship between job resources and turnover intention. The fact that burnout and engagement exhibit different patterns of possible causes and consequences implies that different intervention strategies should be used when burnout is to be reduced or engagement is to be enhanced. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of water and nitrogen management on aggregate size and carbon enrichment of soil in rice‐wheat cropping system
Authors: Tripathy Rojalin , Singh Anil Kumar 
Published: March 2004

AbstractA study was carried out on a silty clay loam soil (Typic Haplustept) to evaluate the effect of farmyard manure (FYM) vis‐à‐vis fertilizer and irrigation application on the soil organic C content and soil structure. The fertilizer treatments comprised of eight different combinations of N and FYM and three water regimes. The results indicated that the application of FYM and increasing N rate increased soil organic carbon (SOC) content. Addition of FYM also increased the percentage of large sized water stable aggregates (> 5 mm) and reduced the percentage of smaller size aggregates. This was reflected in an increase in the mean weight diameter (MWD) and improved soil structure. The organic carbon content in macroaggregates (> 1 mm) was greater compared to microaggregates, and it declined with decrease in size of microaggregates. This difference in organic C content between macro‐ and microaggregates was more with higher N dose and FYM treated plots. The effect of residual FYM on MWD and organic C content of the soil after wheat harvest was not significant. The effect was less in deeper layers compared to surface layers of the soil. MWD was significantly correlated with the SOC content for the top two layers.
Trace element release from forest floor can be monitored by ion exchange resin tubes
Authors: Lang Friederike , Kaupenjohann Martin 
Published: March 2004

AbstractRisk assessment of heavy metal input into forest ecosystems requires information about metal fluxes from the forest floor (organic layer) into the mineral soil. Common methods for the monitoring of element fluxes are generally time‐consuming and expensive. Additionally, the reliability of the results is in part contested especially for trace elements, showing very low concentrations which are sometimes even below analytical detection limit. We used ion exchange resin tubes installed below the forest floor to determine heavy metal and As fluxes at 25 forest monitoring sites in Germany. Chloride tracer experiments and the comparison of our data with throughfall and lysimeter data, determined within the Level II monitoring network, proved the accuracy of our method. Mean trace element fluxes based on the resin method were 50 g As ha–1 yr–1, 2 g Cd ha–1 yr–1, 168 g Cu ha–1 yr–1, 176 g Ni ha–1 yr–1, and 186 g Pb ha–1 yr–1.The results show that the organic layer may change into a source of heavy metals after emission has decreased.
Effects of earthworm activity and P‐solubilizing bacteria on P availability in soil
Authors: Wan Judy H. C. , Wong Ming H. 
Published: March 2004

AbstractThe effects of phosphate solubilizing bacteria (Bacillus megateriumi) (PSB) and earthworms (Pheretima guillelmiandEisenia fetida) on phosphorus (P) turnover and transformation in soil were investigated in a laboratory experiment lasting for 21 days. The treatments included soil +P. guillelmi(SW1), soil +E. fetida(SW2), soil +B. megaterium(SB), soil +P. guillelmi+B. megaterium(SBW1), soil +E. fetida+B. megaterium(SBW2), and the control with sterilized soil (control) only. The results showed that the number ofB. megaterium.was enhanced in all treatments especially those with earthworms added when compared with the control. Activities of acid phosphatase (pH = 6.5) increased in all treatments, especially in the presence ofP. guillelmiwith or without PSB (64 % and 38 %, respectively). Significant increases in both inorganic P and water‐soluble P were observed in treatments involvingB.megaterium.and earthworms when compared with the control. Inoculation of both earthworms and PSB had significant effects on microbial growth, enzymatic activity, and thus enhanced the release of available P. The dual inoculation of earthworms and bacteria further accelerated P transformation. Different performances observed for the earthworm species were probably due to their different feeding habits and physiology.
Adsorption of the Bacillus thuringiensis toxin (Cry1Ab) on Na‐montmorillonite and on the clay fractions of different soils
Authors: Pagel‐Wieder Sibylle , Gessler Frank , Niemeyer Jürgen , Schröder Dietmar 
Published: March 2004

AbstractThe adsorption of the toxin from Bacillus thuringiensis (Bt‐toxin), which is synthesized in genetically modified maize, on sterilized Na‐montmorillonite and on H2O2‐treated and untreated clay fractions of three soils from different sites were studied. All adsorption isotherms can be described by a linear isotherm. Although all clay fractions from the different soils show nearly the same mineralogical composition, we found different affinities ranging from k = 47.7 to k = 366.7 of the adsorbates for the Bt‐toxin. The H2O2‐treated clay fractions show no correlation between the adsorption affinity and the amount of soil organic matter. On the other hand, there is a correlation between the content of organic carbon and the adsorption affinity of the untreated clay fractions. This can be explained by the fact that due to the coatings of soil organic matter on aggregates, the Bt‐toxin polymers are not able to adsorb within the clay aggregates.