bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poor intercellular transport and absence of enhanced antiproliferative activity after non‐viral gene transfer of VP22‐P53 or P53‐VP22 fusions into p53 null cell lines in vitro or in vivo
Authors: Zavaglia David , Lin Erh‐Hsuan , Guidetti Mélanie , Pluquet Olivier , Hainaut Pierre , Favrot Marie‐Christine , Coll Jean‐luc 
Published: March 2005

AbstractBackgroundThe herpes simplex virus type 1 (HSV‐1) VP22 protein has the property to mediate intercellular trafficking of heterologous proteins fused to its C‐ or N‐terminus. We have previously shown improved delivery and enhanced therapeutic effect in vitro and in vivo with a P27‐VP22 fusion protein. In this report, we were interested in studying the spread and biological activity of VP22 fused to the P53 tumor suppressor.MethodsExpression of the VP22‐P53 and P53‐VP22 fusion proteins was shown by Western blot and intercellular spreading was monitored by immunofluorescence on transiently transfected cells. In vitro antiproliferative activity of wild‐type (wt) P53 and P53‐VP22 was assessed by proliferation assays and transactivating ability was studied by a reporter gene test and a gel‐shift assay. Antitumor activity was also tested in vivo by intratumoral injections of naked DNA in a model of subcutaneous tumors implanted in nude mice.ResultsOur results show that the C‐terminal fusion or the N‐terminal P53‐VP22 fusion proteins are not able to spread as efficiently as VP22. Moreover, we demonstrate that VP22‐P53 does not possess any transactivating ability. P53‐VP22 has an antiproliferative activity, but this activity is not superior to the one of P53 alone, in vitro or in vivo.ConclusionsOur study indicates that a gene transfer strategy using VP22 cannot be considered as a universal system to improve the delivery of any protein. Copyright © 2005 John Wiley & Sons, Ltd.
A QSAR‐modeling perspective on cationic transfection lipids. 1. Predicting efficiency and understanding mechanisms
Authors: Horobin Richard W. , Weissig Volkmar 
Published: March 2005

AbstractBackgroundAs gene therapy using viral vectors involves clinical risks, limited DNA‐carrying capacity, and manufacturing problems, non‐viral vectors, including cationic lipids, have been investigated. Unfortunately, these agents have significantly lower transfectional ability and, due to the complexity of the transfectional pathway, no general schemes exist for correlating cationic lipid chemistry with transfectional efficacy.MethodsQuantitative structure–activity relationship (QSAR) analyses were carried out on sets of routinely used, experimental, and unsuccessful cationic lipid vectors taken from the literature. This approach described the amphipathic character, basicity, headgroup size, lipophilicity and shape of cationic lipids using numerical parameters. Compounds were plotted onto various parameter diagrams, and correlations were sought between numerical parameters and transfectional efficiency.ResultsTransfectionally effective cationic lipids fell into restricted zones in various parameter spaces, indicating that amphipathic character, lipid shape and lipophilicity were generally significant factors, whilst basicity and headgroup size were only important for certain compounds. The data supported the general significance of membrane mixing followed by induction of membrane curvature, and the more limited role of osmotic shock, as mechanisms of membrane disruption. QSAR descriptions of effective lipids permitted detailed chemical guidelines for optimizing cationic lipid structure to be given. Limitations of the approach and models are discussed.ConclusionsQSAR modeling indicated that induction of membrane curvature and osmotic shock are important mechanisms for membrane disruption by cationic lipids. The models also allowed specification of chemically detailed guidelines for selection or design of optimal cationic lipids. Copyright © 2005 John Wiley & Sons, Ltd.
Rad51 siRNA delivered by HVJ envelope vector enhances the anti‐cancer effect of cisplatin
Authors: Ito Makoto , Yamamoto Seiji , Nimura Keisuke , Hiraoka Kazuya , Tamai Katsuto , Kaneda Yasufumi 
Published: March 2005

AbstractBackgroundEvery cancer therapy appears to be transiently effective for cancer regression, but cancers gradually transform to be resistant to the therapy. Cancers also develop machineries to resist chemotherapy. Short interfering RNA (siRNA) has been evaluated as an attractive and effective tool for suppressing a target protein by specifically digesting its mRNA. Suppression of the machineries using siRNA may enhance the sensitivity to chemotherapy in cancers when combined with an effective delivery system.MethodsTo enhance the anti‐cancer effect of chemotherapy, we transferred siRNA against Rad51 into various human cancer cells using the HVJ (hemagglutinating virus of Japan, Sendai virus) envelope vector in the presence or absence of cis‐diamminedichloroplatinum(II) (CDDP, cisplatin). The inhibition of cell growth was assessed by a modified MTT assay, counting cell number, or fluorescence‐activated cell sorting (FACS) analysis after Annexin V labeling. The synthetic Rad51 siRNA was also introduced into subcutaneous tumor masses of HeLa cells in SCID mice with or without intraperitoneal injection of CDDP, and tumor growth was monitored.ResultsWhen synthetic Rad51 siRNA was delivered into HeLa cells using the HVJ envelope vector, no Rad51 transcripts were detected on day 2, and Rad51 protein completely disappeared for 4 days after siRNA transfer. When HeLa cells were incubated with 0.02 µg/ml CDDP for 3 h after siRNA transfer, the number of colonies decreased to approximately 10% of that with scrambled siRNA. The sensitivity to CDDP was enhanced in various human cancer cells, but not in normal human fibroblasts. When Rad51 siRNA was delivered into tumors using the HVJ envelope vector, the Rad51 transcript level was reduced to approximately 25%. Rad51 siRNA combined with CDDP significantly inhibited tumor growth when compared to siRNA or CDDP alone.ConclusionsRad51 siRNA could enhance the sensitivity to CDDP in cancer cells both in vitro and in vivo. Our results suggest that the combination of CDDP and Rad51 siRNA will be an effective anti‐cancer protocol. Copyright © 2005 John Wiley & Sons, Ltd.
Replication‐dependent transgene expression from a conditionally replicating adenovirus via alternative splicing to a heterologous splice‐acceptor site
Authors: Carette Jan E. , Graat Harm C. A. , Schagen Frederik H. E. , Abou El Hassan Mohamed A. I. , Gerritsen Winald R. , van Beusechem Victor W. 
Published: March 2005

AbstractBackgroundOncolytic viruses are promising anticancer agents because they selectively kill cancer cells and multiply within a tumor. Their oncolytic potency might be improved by expressing a therapeutic gene from the virus genome. In this regard, proper kinetics and level of transgene expression are important. In addition, expression of cytotoxic transgene products should be confined to cancer cells. Here, we developed oncolytic adenoviruses that provide transgene expression dependent on viral replication.MethodsWe constructed an oncolytic adenovirus that expresses luciferase under regulation of the endogenous major late promoter (MLP) via alternative splicing to an inserted splice‐acceptor site analogous to that of the adenovirus serotype 40 long fiber gene. Splicing of the luciferase transcript was studied by RT‐PCR analysis. Expression was measured in the presence and absence of the flavonoid apigenin, an inhibitor of viral replication.ResultsThe inserted splice‐acceptor site was properly recognized by the adenoviral splicing machinery. Luciferase expression levels were markedly higher than levels obtained with the cytomegalovirus (CMV) promoter, especially at late stages of infection. Inhibiting adenovirus replication reduced luciferase expression levels dramatically by 4 to 5 logs, whereas expression levels with the CMV‐luciferase adenovirus were only moderately affected (2 logs).ConclusionsTransgene delivery using the endogenous late gene expression machinery resulted in an expression pattern distinct from expression driven by the conventional CMV promoter. The high expression levels and strict coupling of expression to viral replication should be useful for adequate monitoring of replication and might provide a platform for the design of armed conditionally replicating adenoviruses (CRAds) with enhanced oncolytic potency. Copyright © 2005 John Wiley & Sons, Ltd.
Decay of oxygen solid solution in plastically deformed silicon
Authors: Yarykin N. , Vdovin V. I. 
Published: March 2005

AbstractDecay of the oxygen solid solution in silicon during annealing at 550–700 °C is studied by the IR absorption technique in the single crystalline samples subjected to the plastic deformation to a high dislocation density at 680 °C. The deformation is shown to significantly enhance the rate of the decay in the whole temperature range studied. Based on the simple model, which assumes the heterogeneous oxygen aggregation at dislocations, the effective oxygen diffusivity is calculated from the experimental data. The activation energy of oxygen diffusion in this temperature range is found to be about 1.6 eV, which is essentially lower than that for the isolated interstitial oxygen atom. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of GaN regrowth on the micro‐facetted GaN template formed by in‐situ thermal etching
Authors: Moon Y. T. , Fu Y. , Yun F. , Dogan S. , Mikkelson M. , Johnstone D. , Morkoç H. 
Published: March 2005

AbstractWe report a study of GaN regrowth on micro‐facetted GaN templates formed by in‐situ thermal etching in a low‐pressure metalorganic chemical vapor deposition system. First, the 1.5 µm‐thick GaN epilayers were grown on c‐plane sapphire substrates. This was followed by an in‐situ thermal etching process under hydrogen and ammonia ambient with the etching time being a parameter. The thermally etched GaN templates showed hexagonal GaN pyramids, which were aligned along the growth direction on the c‐plane substrate. The 3 µm‐thick GaN regrowth was performed on these micro‐facetted GaN templates. The surface of the overgrown GaN was atomically smooth. The full width at half maximum of (102) peak in the X‐ray rocking curve profile decreased from 9.5 to 6.5 arcmin as the thermal etching time increased from 0 to 45 min. Etch pit density measurements revealed that the pit density of regrown GaN decreased by about one order of magnitude, compared to that of the control sample. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of surface passivation on low‐frequency noise properties of AlGaN/GaN high electron mobility transistor structures
Authors: Vitusevich S. A. , Petrychuk M. V. , Danylyuk S. V. , Kurakin A. M. , Klein N. , Belyaev A. E. 
Published: March 2005

AbstractWe investigated low‐frequency noise in passivated and nonpassivated AlGaN/GaN high electron mobility transistor (HEMT) heterostructures grown on SiC substrate. The heterostructure layers are grown without intentionally doping the barrier material and two‐dimensional gas appears at the interface only due to polarization effects. Transmission line model structures with different lengths of the conducting channel were studied in a wide range of temperatures in a linear regime. The magnitude of the noise and Hooge parameter demonstrate different dependence on the distance between contacts in passivated and non‐passivated structures. Noise reduction in the structure for around one order of magnitude after passivation was revealed and different origins of the noise before and after passivation established. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Organic photodiodes on newspaper
Authors: Lamprecht B. , Thünauer R. , Ostermann M. , Jakopic G. , Leising G. 
Published: March 2005

AbstractWe report on the fabrication and characterization of organic photodiodes deposited on ordinary newspaper sheets. Parylene acts as water and chemical barrier layer, an ORMOCER layer serves as an excellent smoothing and base layer for the diodes, which correspond to classical Tang‐type bilayer cells. The photodiodes show excellent diode behaviour in current–voltage measurements of the devices under dark and illumination conditions. The spectral response covers the UV and visible spectral range.magnified image(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An empirical typology of narcissism and mental health in late adolescence
Authors: Lapsley Daniel K. , Aalsma Matthew C. 
Published: March 2005

AbstractA two‐step cluster analytic strategy was used in two studies to identify an empirically derived typology of narcissism in late adolescence. In Study 1, late adolescents () responded to the profile of narcissistic dispositions and measures of grandiosity (“superiority”) and idealization (“goal instability”) inspired by Kohut's theory, along with several College Adjustment Scales and a measure of pathology of separation‐individuation. Cluster analysis revealed three clusters: covert narcissists (), moderate narcissists () and overt narcissists (). Moderate narcissists had significantly lower means scores on indices of anxiety, relationship problem, depression, esteem‐ and family problems and pathology of separation‐individuation. The overt and covert clusters showed comparable levels of dysfunction on most indices of adjustment. This general pattern was replicated in Study 2 (). Moderate narcissists showed a uniform profile of good adjustment, whereas covert and overt narcissist clusters showed a pervasive pattern of dysfunction. Results support the claim that narcissism has “two faces” and that a moderate degree of narcissism is associated with fewer adjustment problems or psychological symptoms. Directions for future research are discussed.
INFLUENCE OF SHADE ON STOMATAL DENSITY, LEAF SIZE AND OTHER LEAF CHARACTERISTICS IN THE MAJOR TROPICAL ROOT CROPS, TANNIA, SWEET POTATO, YAM, CASSAVA AND TARO
Authors: ONWUEME I. C. , JOHNSTON M. 
Published: March 2005

Since shading often occurs under normal growing conditions in various cropping systems (for example, intercropping, alley cropping), field experiments were carried out to determine the effects of shading on stomatal density, leaf size, leaf dry matter, and leaf lamina thickness in the major tropical root and tuber crops, tannia (Xanthosoma sagittifolium), sweet potato (Ipomoea batatas), yam (Dioscorea esculenta), cassava (Manihot esculenta), and taro (Colocasia esculenta). Shading decreased stomatal density in the lower epidermis of tannia, sweet potato, yam and cassava, and in the upper epidermis also in tannia and sweet potato; the upper epidermis of yam and cassava were devoid of stomata. In contrast to the other species, taro under shade had an increased stomatal density in both the upper and lower epidermis, a finding which was confirmed in subsequent pot experiments. This response of taro was postulated as a possible manifestation of greater shade adaptation by the species.For all the species, shading generally resulted in the production of larger (in terms of surface area) but thinner leaves, with a decreased dry matter concentration. For the two species (yam and cassava) that had stomata only on the lower epidermis, normal sun-grown plants had about twice as many stomata per unit area of lower epidermis than did corresponding plants of the other three species. The agronomic and physiological significance of the findings are discussed.
Differential Scanning Calorimetry Study of Phase Transitions Affecting the Quality of Dehydrated Materials
Authors: Roos Yrjö , Karel Marcus 
Published: March 2005

AbstractDifferential scanning calorimetry was used to determine the phase transitions of dried and rehumidified amorphous lactose, sucrose, and a mixture of sucrose and Amioca. Glass‐transition, crystallization, and melting temperatures decreased with increasing moisture content. The time to crystallization of amorphous lactose held isothermally above the glass‐transition temperature decreased as the temperature was increased. Isothermal crystallization time of lactose was a function of the temperature difference between the holding temperature and the glass‐transition temperature independently of moisture content. Amorphous biological materials are metastable showing temperature, moisture content, and time‐dependent phase transitions that affect their drying behavior, stickiness, storage stability, and quality.
Chemical and Biosynthetic Approaches to the Production of Novel Polypeptide Materials
Authors: Mcgrath Kevin P. , Tirrell David A. , Kawai Michio , Mason Thomas L. , Fournier Maurille J. 
Published: March 2005

AbstractThree approaches to the synthesis of the repetitive copolypeptide [‐(GlyAla)3‐ GlyProGlu‐]n (1) are described. Direct chemical synthesis of 1 via classical solution methods required 18 steps and afforded a polydisperse product with an average molecular weight of less than 10 000. Two alternative genetic strategies were also explored. In the first, chemically synthesized DNA oligomers were self‐ligated to produce a population of multimers, which were fitted with translational start and stop signals and inserted into an expression plasmid containing the λ PL promoter and a synthetic ribosome binding site. Transformation of E. coli led to the isolation of a stable recombinant plasmid carrying an insert encoding 12 repeats of sequence 1. Attempts to identify polypeptide 1 after induction of transformed cultures were unsuccessful. A second strategy, generating a tripartite derivative of sequence 1 carrying short N‐and C‐terminal extensions, afforded excellent yields of product. The relative merits of chemical and genetic approaches to repetitive polypeptide materials are discussed.
Improved Bioreaction Kinetics for the Simulation of Continuous Ethanol Fermentation by Saccharomyces cerevisiae
Authors: Warren R. K. , Hill G. A. , Macdonald D. G. 
Published: March 2005

AbstractA kinetic model for the production of ethanol by Saccharomyces cerevisiae has been developed from semiempirical analysis. The values for the parameters in this model were then determined by nonlinear multiple regression using the data of Bazua and Wilke ( 1977). The final equations were μ=0.427s(1‐(p/101.6)1.95)/(0.245+s), YX/p=0.291, and YX/s=0.152(1‐p/302.3). This model was then used to simulate a continuous stirred tank fermentor (CSTF) and compared to other models using the same experimental data but different kinetics. The equations required to use these kinetics in a CSTF with recycle were then developed. From this simulation, it was found that, for a CSTF with recycle, the best configuration to operate is an external recycle, with a low bleed and recycle ratio.
Growth and Fermentation Model for Alginate‐Entrapped Saccharomyces cerevisiae
Authors: Hannoun Betty J. M. , Stephanopoulos Gregory 
Published: March 2005

AbstractA model of growth and fermentation for alginate‐entrapped Saccharomyces cerevisiae is presented. The model is based on Peringer's rate equations (Peringer, P.; et al. Biotechnol. Bioeng. Symp. 1973, 4, 27–42), developed for glucose‐repressed cultures of suspended cells at varying dissolved oxygen concentrations, and was fitted to estimates of growth and fermentation rates for immobilized cells obtained through a combination of experimental measurements and reaction‐diffusion analysis. Immobilized cell fermentation data with alginate beads in suspension compared well with simulations of reaction and diffusion in a similar system incorporating the proposed growth‐fermentation model. In view of these findings, the model was further applied to the simulation of transient and steady‐state operation of a packed‐bed immobilized cell biore‐actor. Results about the effect of operating parameters on bioreactor performance are presented, and implications regarding system design and operation for optimal overall performance are discussed.
Protective Effect of Methylcellulose and Other Polymers on Insect Cells Subjected to Laminar Shear Stress
Authors: Goldblum Seth , Bae Yong‐Kook , Hink W. Fred , Chalmers Jeff 
Published: March 2005

AbstractThe relative sensitivity of two insect cell lines to laminar shear stress was determined, and the protective effect of polymers added to the growth media of two insect cell lines, Trichoplusia ni (TN‐368) and Spodoptera frugiperda (SF‐9), was evaluated. TN‐368 and SF‐9 cells were found to be equally sensitive to laminar shear stress. Methylcellulose [0.5% (w/v) Dow E4M Methocel] and dextran [4.5% (w/v)] increased the resistance of suspended cells to lysis due to laminar shear stress by factors of up to 76 and 28, respectively, compared to cells in media without additives. It was observed that the protective effect of Pluronic F‐68 was concentration‐dependent: 0.2% and 0.3% (w/v) F‐68 increased the resistance of SF‐9 cells to shear stress by factors of 15 and 42, respectively. However, increasing the concentration to 0.5% did not significantly increase the cells' resistance compared to 0.3% (w/v). F‐68 at 0.2% only increased the resistance of TN‐368 cells by a factor of 6. It is believed that the protection is a result of the polymer adsorbing to the cell membrane. None of the polymer additives tested had a significant effect on SF‐9 or TN‐368 growth rate.
Effect of Dissolved Oxygen Control on Growth and Antibiotic Production in Streptomyces clavuligerus Fermentations
Authors: Yegneswaran P. K. , Gray M. R. , Thompson B. G. 
Published: March 2005

AbstractA proportional‐integral control system was used to control dissolved oxygen in a fermentor at constant shear and mass transfer conditions. Growth and antibiotic production in Streptomyces clavuligerus were studied at different dissolved oxygen levels during the fermentation. Three protocols were employed: no‐oxygen control to provide a base case, oxygen controlled to a preset saturation level throughout the fermentation, and oxygen controlled at a high level only during the growth phase. The last protocol was aimed at optimizing the consumption of oxygen. Lower specific growth rates and cephamycin C yields were obtained when dissolved oxygen was controlled at 50% throughout the fermentation, compared to the base case. A 2.4‐fold increase in the final cephamycin yield was observed when dissolved oxygen was controlled at saturation levels during the growth phase, compared to the experiments without dissolved oxygen control. This enhancement in yield was independent of the dissolved oxygen (DO) level after exponential growth, in the range of 50–100% saturation. The most effective control strategy, therefore, was to control DO only during active growth when the biosynthetic enzymes were probably synthesized.