bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Enhancement of Visual Learning by Activation of Protein Kinase C Pathways in Small Groups of Rat Cortical Neurons
Authors: Zhang Guo-rong , Wang Xiaodan , Kong Lingxin , Lu Xiu-gui , Lee Brian , Liu Meng , Sun Mei , Franklin Corinna , Cook Robert G. , Geller Alfred I.
Published: September 2005

Although learning and memory theories hypothesize that memories are encoded by specific circuits, it has proven difficult to localize learning within a cortical area. Neural network theories predict that activation of a small fraction of the neurons in a circuit can activate that circuit. Consequently, altering the physiology of a small group of neurons might potentiate a specific circuit and enhance learning, thereby localizing learning to that circuit. In this study, we activated protein kinase C (PKC) pathways in small groups of neurons in rat postrhinal (POR) cortex. We microinjected helper virus-free herpes simplex virus vectors that expressed a constitutively active PKC into POR cortex. This PKC was expressed predominantly in glutamatergic and GABAergic neurons in POR cortex. This intervention increased phosphorylation of five PKC substrates that play critical roles in neurotransmitter release (GAP-43 and dynamin) or glutamatergic neurotransmission (specific subunits of AMPA or NMDA receptors and myristoylated alanine-rich C kinase substrate). Additionally, activation of PKC pathways in cultured cortical neurons supported activation-dependent increases in release of glutamate and GABA. This intervention enhanced the learning rate and accuracy of visual object discriminations. In individual rats, the numbers of transfected neurons positively correlated with this learning. During learning, neuronal activity was increased in neurons proximal to the transfected neurons. These results demonstrate that potentiating small groups of glutamatergic and GABAergic neurons in POR cortex enhances visual object learning. More generally, these results suggest that learning can be mediated by specific cortical circuits.
Inhibitors of the Mitogen-Activated Protein Kinase Kinase 1/2 Signaling Pathway Clear Prion-Infected Cells from PrPSc
Authors: Nordström Elin K. , Luhr Katarina M. , Ibáñez Carlos , Kristensson Krister
Published: September 2005

Prions represent a unique class of infectious agents in which the normal cellular prion protein (PrPC) is converted to an abnormal isoform (PrPSc), which accumulates in the brain and constitutes the major, if not the only, component of the infectious particle. Factors that still remain to be identified may facilitate the conversion of PrPCto PrPSc. In the present study, we first demonstrated that a growth factor of the neurotrophin family, brain-derived neurotrophic factor (BDNF), stimulates the formation of PrPScin a gonadotropin-releasing hormone-secreting neuronal cell line (GT1-1 cells) infected with the Rocky Mountain Laboratory (RML) strain of scrapie as determined by Western blot analysis. We then observed that the prion-infected cells can be cleared from PrPScby treatment with three inhibitors of mitogen-activated protein kinase kinase 1/2 (MEK1/2) [1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene and 2-(2-amino-3-methyoxyphenyl)-4H-1-benzopyran-4-one, as well as α-[amino[(4-aminophenyl)thio]methylene]-2-(trifluoromethyl) benzeneacetonitrile, which passes the blood–brain barrier], a component of one of the intracellular signaling pathways activated by BDNF. The MEK1/2 inhibitors were also efficient in clearing PrPScfrom prion-infected GT1-1 cells stimulated to accumulate high levels of PrPScby enhanced serum concentrations in the medium or by the use of a serum-free neuron-specific neurobasal medium. PrPScdid not reappear in the cultures within 5 weeks after completion of treatment. We conclude that inhibitors of the MEK1/2 pathway can efficiently and probably irreversibly clear PrPScfrom prion-infected cells. The MEK pathway may therefore be a suitable target for therapeutic intervention in prion diseases.
A New Era in the Ethics of Human Embryonic Stem Cell Research
Authors: Lo Bernard , Zettler Patricia , Cedars Marcelle I. , Gates Elena , Kriegstein Arnold R. , Oberman Michelle , Reijo Pera Renee , Wagner Richard M. , Wuerth Mary T. , Wolf Leslie E. , Yamamoto Keith R.
Published: September 2005

Scientific progress in human embryonic stem cell (hESC) research and increased funding make it imperative to look ahead to the ethical issues generated by the expected use of hESCs for transplantation. Several issues should be addressed now, even though phase I clinical trials of hESC transplantation are still in the future. To minimize the risk of hESC transplantation, donors of materials used to derive hESC lines will need to be recontacted to update their medical history and screening. Because of privacy concerns, such recontact needs to be discussed and agreed to at the time of donation, before new hESC lines are derived. Informed consent for phase I clinical trials of hESC transplantation also raises ethical concerns. In previous phase I trials of highly innovative interventions, allegations that trial participants had not really understood the risk and benefits caused delays in subsequent trials. Thus, researchers should consider what information needs to be discussed during the consent process for hESC clinical trials and how to verify that participants have a realistic understanding of the study. Lack of attention to the special ethical concerns raised by clinical trials of hESC transplantation and their implications for the derivation of new hESC lines may undermine or delay progress toward stem cell therapies.
Spatial Variability of Long‐Term Chloride Transport under Semiarid Conditions: Pedon Scale
Authors: Dyck M. F. , Kachanoski R. G. , de Jong E.
Published: September 2005

Knowledge about the magnitude and variability of water and solute fluxes in semiarid environments is required to assess the environmental risk associated with contaminants in the vadose zone. The purpose of this study was to examine the pedon‐scale spatial variability in the transport of a chloride tracer after 34 yr at a site 50 km southwest of Saskatoon, SK. Soil cores were taken from two, pedon‐scale transects (transects encompassing many pedons), and solute transport was quantified for each depth breakthrough curve using the method of moments. Modal transport depth (depth of peak concentration) did not vary significantly over the length of the transects (average = 1.34 m), indicating a relatively uniform soil water balance at the pedon scale. Therefore, trends in central moments (mean travel depth (E[z]), and variance about E[z]) were attributed to spatial variations in soil layering. Transport variance was negatively correlated (P < 0.05) to the thickness of a fine‐textured, varved layer. The high water content (transport volume) of the varved layer decreased the velocity of the leading edge of the solute depth breakthrough curve which, over time, decreased V[z]. The two‐dimensional distribution of the chloride shows that the estimated horizontal velocity of the chloride pulse (approximately 25 mm yr−1) is more than twice the estimated downward, vertical velocity (approximately 11 mm yr−1). The large horizontal flow component is attributed to anisotropy in soil hydraulic properties. The significant influence of layers on convective and dispersive solute fluxes in a low flow, semiarid environment under natural conditions, complements previous observations in high flow field experiments where two‐ and three‐dimensional flow occurred along layer boundaries, and suggests anisotropy should be incorporated into transport models.
Social and reproductive factors affecting cortisol levels in wild female golden lion tamarins (Leontopithecus rosalia)
Authors: Bales Karen L. , French Jeffrey A. , Hostetler Caroline M. , Dietz James M.
Published: September 2005

The steroid hormone cortisol has been associated with different levels of “stress” as well as different reproductive conditions in many primates. In callitrichids, cortisol has more often been reflective of female reproductive status than of chronic stress. In this study, we addressed the hypothesis that wild golden lion tamarin (Leontopithecus rosalia) females, whose social structure is characterized by low aggression and high social support, would not show rank (“stress”)‐related differences in glucocorticoids but would show reproductive changes. We collected 710 fecal samples from 22 adult females in Poço das Antas Reserve, Brazil, and nearby reintroduction areas, and assayed them for cortisol. Differences in cortisol levels were found between different reproductive conditions. Females in the first trimester of pregnancy had lower cortisol levels than nonpregnant females, although we did not differentiate between basal and ovulating levels in nonpregnant females. Cortisol rose in the third trimester of pregnancy. Primiparous females had a higher rise in the third trimester than multiparous females. No differences in cortisol levels were found among dominant females, ovulatory subordinate females, or anovulatory subordinate females. These results are similar to those obtained in other studies of callitrichid females. The lack of differences in cortisol excretion between dominants and subordinates is likely due to the low levels of overt aggression and the high level of social support available to subordinate females. Am J Primatol 67:25–35, 2005. © 2005 Wiley‐Liss, Inc.
Behavioral strategies and hormonal profiles of dominant and subordinate common marmoset (Callithrix jacchus) females in wild monogamous groups
Authors: Sousa Maria Bernardete Cordeiro , Albuquerque Ana Claudia Sales da Rocha , Albuquerque Fabiola da Silva , Araujo Arrilton , Yamamoto Maria Emilia , Arruda Maria de Fatima
Published: September 2005

New insights into the mating systems of common marmosets suggest that they are mainly monogamous, although polygyny and polyandry occasionally occur. Long‐term monitoring of wild common marmosets has shown that some reports of polygynous groups (i.e., groups that contain more than one reproducing female) in fact indicate an unbalanced reproductive output associated with extragroup copulation. In this study we describe the behavioral and hormonal profiles of common marmoset (Callithrix jacchus) females living in three wild monogamous groups (Q, PBf, and T), varying from five to 11 individuals, at Nísia Floresta field station, RN, Brazil. The mating system of the groups was previously characterized in terms of affiliative, sexual, and mate‐guarding behaviors. Behavioral data were collected once a week, and fecal samples were collected at least twice a week for 10–16 months, depending on the group. A preferential allogrooming relationship was recorded between dominant males and females. Under field conditions the reproductive inhibition of subordinate females appears to be more behavioral than hormonal, since subordinate females of the three groups ovulated and two conceived during the study. In these cases, the subordinate and dominant females reproduced 1 month apart, and infanticide (one case confirmed and one suspected) appeared to be part of the reproductive strategy of dominant females. Following the infanticide, ovarian inhibition (group T) or emigration and return to the natal group (group PBf) were observed. In the third group (Q) the subordinate female showed hormonal profiles compatible with pregnancy, but no infants were seen. These findings reflect the different alternatives that wild subordinate common marmoset females use to reproduce. Am. J. Primatol. 67:37–50, 2005. © 2005 Wiley‐Liss, Inc.
Behavioral indicators of ovarian phase in white‐faced capuchins (Cebus capucinus)
Authors: Carnegie Sarah D. , Fedigan Linda M. , Ziegler Toni E.
Published: September 2005

In many primate species, conspicuous behavioral and/or morphological changes are indicators of the fertile phase of the female cycle. However, several primate species, such as the white‐faced capuchin, lack these cues. This is referred to as “concealed ovulation,” and is argued to be a reproductive strategy that confuses paternity and lowers the risk of infanticide. We studied 10 adult female white‐faced capuchins in Santa Rosa National Park, Costa Rica, from January to June 2002. We determined their ovarian cycling patterns by analyzing fecal ovarian hormones, and compared simultaneously collected behavioral data to determine which, if any, cues females use to signal their fertile phases. We found that four females cycled during the study period but ceased to cycle without becoming pregnant. We considered several explanations for the lack of conception during our study, including reproductive seasonality. We found that female C. capucinus showed only small increases in rates of affiliative/proceptive behaviors directed toward adult males during their periovulatory phases. The best indicator of cycle phase was a significant increase in male affiliative behaviors (e.g., following and grooming bouts) and sexual behaviors (e.g., copulations and courtship displays) directed toward females during the periovulatory phase compared to the nonovulatory phase. Our finding that females exhibit little proceptive behavior, but that copulations and male courtship are nonetheless concentrated in periovulatory phases suggests that even though females do not provide behavioral and morphological cues to ovulation, males are still able to detect it. Infanticide occurs with some frequency in these monkeys, and there is evidence for postconceptive mating as a female strategy to lower risk of infanticide via paternity confusion. However, despite this occurrence of nonconceptive mating and the absence of female cues to ovulation, truly concealed ovulation does not appear to be characteristic of this study population of white‐faced capuchins. Am. J. Primatol. 67:51–68, 2005. © 2005 Wiley‐Liss, Inc.
Female testosterone, dominance rank, and aggression in an Ethiopian population of hybrid baboons
Authors: Beehner Jacinta C. , Phillips‐Conroy Jane E. , Whitten Patricia L.
Published: September 2005

Studies on the relationship between female testosterone (T) measures and behavior, particularly in free‐ranging primate populations, remain scant. In this study we used fecal steroid analysis to examine the effects of seasonal, reproductive, and social factors on female T in a group of free‐ranging hybrid baboons (Papio sp.) in the Awash National Park of Ethiopia. We collected behavioral and hormonal data from 25 adult females across an 11‐month period. Solid phase extraction and radioimmunoassay (RIA) techniques were used to quantify T in 776 fecal samples collected weekly from each female. The results indicate that 1) the females had elevated T during pregnancy and during the wet season relative to other periods, 2) female dominance rank was positively related to T measures, and 3) female T and aggression were positively related within subjects but not across subjects. Higher T concentrations during pregnancy are consistent with other published profiles of pregnancy in primates. In combination with data on foraging, wet season increases in T may indicate contest competition for females. The rank–T relationship may be mediated by supplants or aggression. Finally, we discuss the different interpretations of the hormone–behavior relationship based on within‐ and across‐subject analyses. Am. J. Primatol. 67:101–119, 2005. © 2005 Wiley‐Liss, Inc.
Titelbild: A Template‐Based Electrochemical Method for the Synthesis of Multisegmented Metallic Nanotubes (Angew. Chem. 37/2005)
Authors: Lee Woo , Scholz Roland , Nielsch Kornelius , Gösele Ulrich
Published: September 2005

Gleichmäßige Anordnungen von Metallnanoröhren …︁ werden mit einer neu entwickelten elektrochemischen Methode erhalten. In ihrer Zuschrift auf S. 6204 ff. berichten W. Lee et al. über die Synthese mehrfach segmentierter Metallnanoröhren mit bimetallischer Schichtung entlang der Röhrenachse. Ihr Ansatz beruht auf der bevorzugten elektrochemischen Abscheidung eines Metalls längs der Porenwände von Aluminiumoxid‐Membranen in Gegenwart von Metallnanopartikeln auf den Porenwänden.
Cover Picture: A Template‐Based Electrochemical Method for the Synthesis of Multisegmented Metallic Nanotubes (Angew. Chem. Int. Ed. 37/2005)
Authors: Lee Woo , Scholz Roland , Nielsch Kornelius , Gösele Ulrich
Published: September 2005

Uniform arrays of metallic nanotubes can be prepared with a newly developed electrochemical method. In their Communication on page 6050 ff., W. Lee et al. report the preparation of multisegmented metallic nanotubes with a bimetallic stacking configuration along the nanotube axis. The approach is based on the preferential electrodeposition of metal along the pore walls of anodic alumina membranes in the presence of metallic nanoparticles on the nanochannel surfaces.
Effects of omeprazole or cola beverage on the pharmacokinetics of oral DA‐8159, a new erectogenic, in rats
Authors: Lee Joo H. , Bae Soo K. , Kwon Jong W. , Kim Won B. , Lee Myung G.
Published: September 2005

The changes in pharmacokinetics of DA‐8159 by omeprazole with respect to inhibition of CYP3A1/2 in rats were evaluated. After oral administration of DA‐8159 at dose of 30 mg/kg to rats pretreated with oral omeprazole at 30 mg/kg for 1 week, the total area under the plasma concentration–time curve from time zero to time infinity (AUC) of DA‐8159 was significantly greater (37.5% increase) than that in control rats. This could be due to inhibition of metabolism of DA‐8159 by inhibition of CYP3A1/2 by omeprazole. The AUCDA‐8164 (a metabolite of DA‐8159)/AUCDA‐8159 ratio was also smaller (32.4% decrease) with omeprazole. After oral administration of DA‐8159 at a dose of 30 mg/kg to rats without or with cola beverage, the pharmacokinetic parameters of DA‐8159 and DA‐8164 were not significantly different between two groups of rats. This suggested that cola beverage did not have any considerable effects on CYP3A1/2 in rats. Copyright © 2005 John Wiley & Sons, Ltd.
Liquid chromatographic separation and UV determination of certain antihypertensive agents
Authors: Bhushan R. , Gupta Deepak , Singh Shravan Kumar
Published: September 2005

Three antihypertensive agents were extracted and isolated from commercial formulations. These were purified and characterized by melting point, λmax and IR. The percentage recovery by extraction process was in the range 81–91%. Active ingredients from binary formulations were separated by RP‐HPLC using methanol–water (50:50 v/v) and by TLC using CHCl3–CH3OH (6:1) as mobile phase. Detection was by UV at 210 nm in HPLC, and by iodine vapors in TLC. The solvent conditions from TLC were transferred to open column chromatographic separation. Quantitative determination was carried out using TLC and column chromatography supplemented with UV spectrophotometry. Recovery was in the range 82–93%. Two combination of drugs, viz. amlodipine + ramipril and amlodipine + enalapril, were separated by the three modes of liquid chromatography. The percentage recovery was in the range 80–92% by open column. Copyright © 2005 John Wiley & Sons, Ltd.
A rapid HPLC method with fluorometric detection for determination of plasma itraconazole and hydroxy‐itraconazole concentrations in cystic fibrosis children with allergic bronchopulmonary aspergillosis
Authors: Redmann Stefanie , Charles Bruce G.
Published: September 2005

The development and validation of a simple, rapid and selective high‐performance liquid chromatography (HPLC) method is described for the quantitation of itraconazole and hydroxy‐itraconazole in 100 µL of plasma from a paediatric population. The mobile phase of methanol (75% v/v) and water (25% v/v) was pumped at 1 mL/min through a C18 Symmetry™ (3.9 mm i.d. × 150 mm) cartridge. Using a protein‐precipitation method, 100 µL internal standard (IS) solution (R051012, 555 µg/L in acetonitrile) were added to 100 µL of plasma followed by 10 µL zinc sulphate solution (20% w/v). Itraconazole, hydroxy‐itraconazole and IS eluted at 4.7, 8.3 and 12.5 min, respectively and were detected ßuorometrically at 250 nm (excitation) and 380 nm (emission). Recoveries were 87.1–96.7%. Calibrations in drug‐free plasma were linear (r2 > 0.99) from 50 to 2000 µg/L, using 1/c2 (c = concentration) weighting. Intraday and interday imprecision (CV%) was 4.8–17.3 and 6.3–16.6% for itraconazole, and 4.6–17.9 and 7.02–18.4% for hydroxy‐itraconazole. Inaccuracy was −7.1 to −14.7% for itraconazole and −0.1 to −9.7% for hydroxy‐itraconazole. The clinical application of this method was demonstrated by measurement of itraconazole and hydroxy‐itraconazole in plasma samples drawn from paediatric cystic fibrosis patients, who were prescribed itraconazole for treatment of allergic bronchopulmonary aspergillosis. Copyright © 2005 John Wiley & Sons, Ltd.
Palladium(0)‐Catalyzed Cycloisomerization of Enallenes
Authors: Närhi Katja , Franzén Johan , Bäckvall Jan‐E.
Published: September 2005

A novel palladium(0)‐catalyzed cycloisomerization of enallenes has been developed. This reaction, catalyzed by [Pd(dba)2] (dba=dibenzylideneacetone) in acetic acid, results in the formation of cyclopentene derivatives and [n.3.0]bicyclic systems (n=3, 4) in good to high yields. The carbon–carbon bond‐forming step is highly stereoselective to give cis‐fused bicyclic systems. The presence of acetic acid as solvent and dba as ligand for palladium(0) turned out to be essential for the reaction in order to provide good reactivity and regioselectivity.
Internalization of a Peptide into Multilamellar Vesicles Assisted by the Formation of an α‐Oxo Oxime Bond
Authors: Richard Antoine , Bourel‐Bonnet Line
Published: September 2005

As part of a drug‐delivery project, we designed and synthesised a novel hydroxylamine cholesterol‐based anchor to ensure the chemoselective ligation of recognition patterns onto multilamellar vesicles by oxime ligation. The entry of a glyoxylyl peptide into the vesicles was unexpectedly assisted by the formation of the α‐oxo oxime bond. We studied extensively the kinetic and thermodynamic aspects of this phenomenon. Briefly, for a glyoxylyl peptide, the speed and ability to enter the vesicle were dependent upon 1) the presence of a hydroxylamine anchor of the type CholE3ONH2, 2) the amount of peptide engaged in the ligation and 3) the flip‐flop motion permitted by the different formulations, in which the presence of cholesterol seems to play an important role.
Total Synthesis of (+)‐Batzelladine A and (−)‐Batzelladine D, and Identification of Their Target Protein
Authors: Shimokawa Jun , Ishiwata Takanori , Shirai Koji , Koshino Hiroyuki , Tanatani Aya , Nakata Tadashi , Hashimoto Yuichi , Nagasawa Kazuo
Published: September 2005

Asymmetric total synthesis of batzelladine A (1) and batzelladine D (2) has been achieved. Our synthesis of batzelladines features 1) stereoselective construction of the cyclic guanidine system by means of successive 1,3‐dipolar cycloaddition reaction and subsequent cyclization, 2) direct esterification of the bicyclic carboxylic acid 35 with the guanidine alcohol 8 or 59 to construct the whole carbon skeleton of batzelladines, and 3) one‐step formation of the α,β‐unsaturated aldehyde 53 from the primary alcohol 47 with tetra‐n‐propylammoniumperruthenate (TPAP), providing an efficient route to the left‐hand bicyclic guanidine alcohol of batzelladine A (1). With the synthetic compounds 1 and 2 in hand, their target protein was examined by using immobilized CD4 and gp120 affinity gels. The results indicated that batzelladines A (1) and D (2) bind specifically to CD4.
Characterizing the three‐dimensional organization of telomeres
Authors: Vermolen B. J. , Garini Y. , Mai S. , Mougey V. , Fest T. , Chuang T. C.‐Y. , Chuang A. Y.‐C. , Wark L. , Young I. T.
Published: September 2005

Background

Quantitative analysis can be used in combination with fluorescence microscopy. Although the human eye is able to obtain good qualitative results, when analyzing the spatial organization of telomeres in interphase nuclei, there is a need for quantitative results based on image analysis.

Methods

We developed a tool for analyzing three‐dimensional images of telomeres stained by fluorescence in situ hybridization in interphase nuclei with DNA counterstained with 4′,6‐diamidino‐2‐phenylindole. After deconvolution of the image, we segmented individual telomeres. From the location of the telomeres we derived a distribution parameter ρT, which indicated whether the telomeres were in a disk (ρT ≫ 1) or not (ρT ≈ 1). We sorted mouse lymphocyte nuclei and measured ρT. We also performed a bromodeoxyuridine synchronous cell sorting experiment on live cells and measured ρT at several instances.

Results

Measuring ρT for nuclei in G0/G1, S, and G2 produced 1.4 ± 0.1, 1.5 ± 0.2, and 14 ± 2, respectively, showing a significant difference between G2 and G0/G1 or S. For the bromodeoxyuridine synchronous cell sorting experiment, we found a cell cycle dependency of ρT and a correlation between ρT and an observer.

Conclusions

In this study we present a quantitative method to characterize the organization of telomeres using three‐dimensional imaging, image processing, and image analysis. © 2005 International Society for Analytical Cytology
Novel calibration method for flow cytometric fluorescence resonance energy transfer measurements between visible fluorescent proteins
Authors: Nagy Peter , Bene László , Hyun William C. , Vereb György , Braun Manuela , Antz Christof , Paysan Jacques , Damjanovich Sándor , Park John W. , Szöllsi János
Published: September 2005

Background

The combination of fluorescence resonance energy transfer (FRET) and flow cytometry offers a statistically firm approach to study protein associations. Fusing green fluorescent protein (GFP) to a studied protein usually does not disturb the normal function of a protein, but quantitation of FRET efficiency calculated between GFP derivatives poses a problem in flow cytometry.

Methods

We generated chimeras in which cyan fluorescent protein (CFP) was separated by amino acid linkers of different sizes from yellow fluorescent protein (YFP) and used them to calibrate the cell‐by‐cell flow cytometric FRET measurements carried out on two different dual‐laser flow cytometers. Then, CFP‐Kip1 was coexpressed in yeast cells with YFP and cyclin‐dependent kinase‐2 (Cdk2) and served as a positive control for FRET measurements, and CFP‐Kip1 coexpressed with a random peptide fused to YFP was the negative control.

Results

We measured donor, direct, and sensitized acceptor fluorescence intensities and developed a novel way to calculate a factor (α) that characterized the fluorescence intensity of acceptor molecules relative to the same number of excited donor molecules, which is essential for quantifying FRET efficiency. This was achieved by calculating FRET efficiency in two different ways and minimizing the squared difference between the two results by changing α. Our method reliably detected the association of Cdk2 with its inhibitor, Kip1, whereas the nonspecific FRET efficiency between Cdk2 and a random peptide was negligible. We identified and sorted subpopulations of yeast cells showing interaction between the studied proteins.

Conclusions

We have described a straightforward novel calibration method to accurately quantitate FRET efficiency between GFP derivatives in flow cytometry. © 2005 International Society for Analytical Cytology
Fluorescence lifetime imaging in an optically sectioning programmable array microscope (PAM)
Authors: Hanley Quentin S. , Lidke Keith A. , Heintzmann Rainer , Arndt‐Jovin Donna J. , Jovin Thomas M.
Published: September 2005

Background

The programmable array microscopes (PAMs) are a family of instruments incorporating arbitrary control of the patterns of illumination and/or detection. The PAM can be used in sectioning and nonsectioning modes, thereby constituting a useful platform for fluorescence lifetime imaging.

Methods and Results

We used a PAM for acquisition of optically sectioned and widefield fluorescence lifetime images, in which contrast was increased predominantly by suppressing out‐of‐focus light contributions. We simulate, display, and discuss the effects of blurring and fluorophore heterogeneity on lifetime imaging in widefield and confocal configurations.

Conclusion

Sectioning improves the quality of lifetime images of samples with multiple fluorophores or spatially varying Förster resonance energy transfer. © 2005 International Society for Analytical Cytology.
Biphasic calcium response of platelet‐derived growth factor stimulated glioblastoma cells is a function of cell confluence
Authors: Vereb György , Feuerstein Burt G. , Hyun William C. , Fulwyler Mack J. , Balázs Margit , Szöllősi János
Published: September 2005

Background

Previous reports have linked the spiking or two‐phased character of calcium transients evoked by platelet‐derived growth factor (PDGF) to the position of cells in the cell cycle without regard to cell–cell contact and communication. Because cell confluence can regulate growth factor receptor expression and dephosphorylation, we investigated the effect of cell culture confluence and cell cycle on calcium responses of PDGF‐BB–stimulated A172 glioblastoma cells.

Methods

Digital imaging cytometry was used to correlate the peak and duration of calcium response with bromodeoxyuridine positivity and DNA content and with culture confluence on a cell‐by‐cell basis.

Results

In serum‐starved cultures, complete two‐phase calcium signals and shorter, lower spikes occurred independent of cell cycle phase. However, the confluence of cell culture seemed essential for inducing a complete response because cells in sparse cultures exhibited mostly short spikes with lower peaks or no transients at all.

Conclusion

Because cell confluence, by virtue of cell–cell contacts, is assumed to be an important regulator of proliferation, one is tempted to speculate that in transformed cells the ability to produce stronger growth signals upon reaching confluence and facing contact inhibition could provide a proliferative advantage. © 2005 International Society for Analytical Cytology
DPSS yellow‐green 561‐nm lasers for improved fluorochrome detection by flow cytometry
Authors: Telford William , Murga Matilde , Hawley Teresa , Hawley Robert , Packard Beverly , Komoriya Akira , Haas Fred , Hubert Charles
Published: September 2005

Introduction

Blue‐green 488‐nm laser sources are widespread in flow cytometry but suffer some drawbacks for cell analysis, including their excitation of endogenous proteins (resulting in high cellular autofluorescence) and their less‐than‐optimal coincidence with the excitation maxima of commonly used fluorochromes, including the phycoerythrins (PE). Longer wavelength lasers such as green helium–neons and, more recently, diode‐pumped solid state (DPSS) 532‐nm sources have previously been employed to overcome these difficulties and improve overall sensitivity for PE. In this study, we evaluate an even longer wavelength DPSS 561‐nm for its ability to improve PE and DsRed fluorescent protein detection sensitivity.

Methods

A DPSS 561‐nm laser emitting at 10 mW was mounted onto a BD LSR II. Mouse thymoma cells labeled with cell surface marker antibodies conjugated to the R‐ and B‐forms of PE were analyzed and compared with conventional 488‐nm excitation using the same bandpass filters and signal travel distances. A similar analysis was carried out with cell lines expressing the red fluorescent protein DsRed, several green‐yellow excited low molecular weight fluorochromes, and a rhodamine‐based caspase substrate. Additionally, cells labeled with PE and co‐labeled with fluorescein or simultaneously expressing green fluorescent protein (GFP) were analyzed to determine if PE excitation at 561 nm with simultaneous fluorescein/GFP detection was feasible.

Results

The DPSS 561‐nm laser gave a several‐fold improvement in the fluorochrome to autofluorescence ratios between PE‐labeled cells and unlabeled controls. Analysis of cells expressing the fluorescent protein DsRed with the DPSS 561‐nm source gave a 6–7‐fold improvement in sensitivity over 488‐nm excitation, and gave excellent excitation of yellow‐green excited fluorochromes and rhodamine‐based physiological probes. Yellow‐green laser light also caused virtually no impingement on the spatially separated fluorescein/GFP detector, a significant problem with green laser sources, and also allowed simultaneous analysis of GFP and PE with virtually no signal overlap or requirement for color compensation.

Conclusions

DPSS 561‐nm laser excitation gave significantly improved sensitivity for both PE‐labeled and DsRed expressing cells, with little contamination of a typical fluorescein/GFP detector. Published 2005 Wiley‐Liss, Inc.
Melanoma cell necrosis facilitates transfer of specific sets of antigens onto MHC class II molecules of dendritic cells
Authors: Röhn Till A. , Schadendorf Dirk , Sun Yuansheng , Nguyen Xuan Duc , Roeder Daniel , Langen Hanno , Vogt Anne B. , Kropshofer Harald
Published: September 2005

Vaccine strategies that target dendritic cells (DC) in order to elicit immunity against tumors are the subject of intense research. For the induction and maintenance of anti‐tumor immunity, CD4+ helper T cells are often required, which need to see appropriate MHC class II‐peptide complexes on DC. So far, it remained widely unclear what type of tumor cells can feed the MHC class II processing pathway of DC with what type of antigens. Here, we report that peptide loading onto MHC class II molecules of myeloid DC is facilitated by melanoma cells undergoing necrotic rather than apoptotic cell death. Importantly, the set of MHC class II‐associated peptides induced by necrotic tumor cells differed from those found upon engagement of apoptotic tumor cells. This may be due to the fact that only necrotic cells liberated heat shock proteins, which bind tumor‐derived peptides and thereby may promote processing by DC. The potential of DC to activate T cells was kinetically controlled through their antigen receptivity: CD4+ T cells were easily stimulated upon encountering antigen early in DC maturation, whereas antigen capture at later maturation stages favored activation of CD8+ T cells. These findings may aid in designing future vaccination strategies and in identifying novel tumor‐specific helper T cell antigens.
Assessment of CD8 involvement in T cell clone avidity by direct measurement of HLA‐A2/Mage3 complex density using a high‐affinity TCR like monoclonal antibody
Authors: Bernardeau Karine , Gouard Sébastien , David Gaëlle , Ruellan Anne‐Lise , Devys Anne , Barbet Jacques , Bonneville Marc , Chérel Michel , Davodeau François
Published: September 2005

Peptide affinity for MHC molecules determines the number of MHC/peptide complexes stabilized at the cell surface in in vitro tests or in vaccination protocols. We isolated a high affinity monoclonal antibody specific for the HLA‐A2/Mage3 complex that enables an equilibrium binding assay to be performed on T2 cell line loaded with a range of Mage3 peptides. Binding of Mage3 to the HLA‐A2 molecule can be modeled by a standard receptor‐ligand interaction characterized by an affinity constant. This model enables the measurement of the affinity of other immunogenic peptides for HLA‐A2 by a competition test and the calculation of the density of complexes stabilized at the T2 cell surface for all peptide concentrations. Quantification of the HLA‐A2/Mage3 complexes at target cell surfaces was used to estimate the number of complexes required to reach cytotoxicity ED50 of human T cell clones sorted from an unprimed repertoire. We confirm with this antibody the direct relationship between clone avidity and TCR affinity, and the moderate contribution of the CD8 co‐receptor in the reinforcement of TCR‐MHC/peptide contact. Nevertheless, CD8 plays a critical role in the amplification of the specific signal to establish an efficient T cell response at low specific complex densities found in physiological situations.
Clinical applications of neuroimaging with susceptibility‐weighted imaging
Authors: Sehgal Vivek , Delproposto Zachary , Haacke E. Mark , Tong Karen A. , Wycliffe Nathaniel , Kido Daniel K. , Xu Yingbiao , Neelavalli Jaladhar , Haddar Djamel , Reichenbach Jürgen R.
Published: September 2005

Susceptibility‐weighted imaging (SWI) consists of using both magnitude and phase images from a high‐resolution, three‐dimensional, fully velocity compensated gradient‐echo sequence. Postprocessing is applied to the magnitude image by means of a phase mask to increase the conspicuity of the veins and other sources of susceptibility effects. This article gives a background of the SWI technique and describes its role in clinical neuroimaging. SWI is currently being tested in a number of centers worldwide as an emerging technique to improve the diagnosis of neurological trauma, brain neoplasms, and neurovascular diseases because of its ability to reveal vascular abnormalities and microbleeds. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Managing enterprise resource planning systems
Authors: Dery Kristine , Grant David , Hall Richard , Wailes Nick
Published: September 2005

The last decade has seen a dramatic growth in the number of organizations adopting Enterprise Resource Planning systems (ERPs).

To date, much of the research on ERPs has focused on the process of implementation, with relatively little attention given to their ongoing impact on organizations or how to effectively manage these systems over time. The papers in this special issue explore these issues.

ERPs require a considerable financial investment and produce widespread change in organizations. The papers in this special issue suggest that for organizations to gain strategic benefit from ERPs, managers have to be prepared to make a long‐term investment of organizational resources and to develop the capabilities necessary to manage them.

Copyright © 2005 John Wiley & Sons, Ltd.
Determination of 12 pueraria components by high‐performance liquid chromatography‐mass spectrometry
Authors: Lin Ching‐Che , Wu Chuan‐I. , Sheu Shuenn‐Jyi
Published: September 2005

Puerariae radix, a commonly used Chinese herb drug derived from the dried root of legume plant, contains a series of isoflavones as its chief pharmacologically active constituents. Using 12 pueraria components as markers, an LC‐UV‐MS method requiring less than 60 min, was developed for estimating the quality of pueraria samples within 60 min. Extracts were analyzed using a Cosmosil 5C18‐MS column, by gradient elution with an aqueous solution of acetic acid and methanol–ACN at a flow‐rate of 1.0 mL/min. Peaks were detected at 254 nm and each peak was identified by LC/MS. The reproducibilities (RSD) of this proposed method, on the basis of peak‐area ratios from six replicate injections, were 0.93–1.42% (intraday) and 1.05–1.63% (interday) at a detection limit of 0.12–0.78 μg/mL. Most of the markers used in this study can be classified, respectively, into three major categories, namely, isoflavones, O‐glycosidic isoflavones, and C‐glycosidic isoflavones. The structures of the compounds were determined from LC‐MS fragmentation data and data from the literature.
Comparing monolithic and microparticular capillary columns for the separation and analysis of peptide mixtures by liquid chromatography‐mass spectrometry
Authors: Toll Hansjörg , Wintringer Reiner , Schweiger‐Hufnagel Ulrike , Huber Christian G.
Published: September 2005

A mixture of ten proteins was trypsinized and injected onto poly‐(styrene‐divinylbenzene) monolithic columns (60×0.20 or 0.10 mm ID) and a column packed with C18 silica particles (75×0.075 mm ID), respectively. The columns were eluted at 200–2000 nL/min with gradients of ACN in 0.050% TFA. Eluting peptides were detected by ESI‐MS/MS and subsequently identified by database searching. The 100 μm ID monolithic column showed the highest cumulative Mowse scores based on the highest ion scores for the peptides and the largest number of identified peptides. It is shown that the number of identified peptides strongly depends on the dynamic range within the peptide mixture. In consequence, all proteins were identified in a mixture of relatively balanced analyte amounts (12.5–80 fmol) whereas only peptides for six out of ten proteins were found in a sample of high‐dynamic range (0.65–270 fmol). The 100 μm monolithic column showed the highest reproducibility for peptide identifications in three consecutive runs. Depending on sample amount, 57–72% of the identified peptides were detectable in each of the three runs of triplicate analyses. The results demonstrate the high suitability of 100 μm monolithic columns for high‐resolution peptide separations in proteomic research.
Simultaneous determination of carotenoids, tocopherols, and γ‐oryzanol in crude rice bran oil by liquid chromatography coupled to diode array and mass spectrometric detection employing silica C30 stationary phases
Authors: Stöggl Wolfgang , Huck Christain , Wongyai Surapote , Scherz Heimo , Bonn Günther
Published: September 2005

Crude rice bran oil contains tocopherols (vitamin E), carotenoids (vitamin A), and phytosterols, which possess antioxidant activities and show promising effects as preventive and therapeutic agents. The aim of this work was to establish methods and to compare C18 and C30 silica stationary phases in order to separate and detect tocopherols, carotenoids, and γ‐oryzanol in one single run. Comparing RP‐LC on silica C18 and C30, higher resolution between all target compounds was obtained using the C30 stationary phase. Methanol was used as eluent and the elution strength was increased by the addition of tert‐butyl methyl ether for highly hydrophobic analytes such as γ‐oryzanol. Detection was accomplished by diode array detection from 200 to 500 nm. Absorbance maxima were found at 295 nm for tocopherols, 324 nm for γ‐oryzanol, and 450 nm for carotenoids. Furthermore, compounds were characterized and identified on the basis of their UV‐spectra. Both RP systems were coupled to MS (LC‐MS) by using an atmospheric pressure chemical ionization interface.
Corrosion characteristics of the wrought Ni‐Cr‐Mo alloys
Authors: Crook P.
Published: September 2005

This paper concerns the wrought, nickel‐chromium‐molybdenum (Ni‐Cr‐Mo) alloys, a family of materials with a long history of use in the chemical process industries. Their attributes include resistance to the halogen acids and resistance to pitting, crevice attack, and stress corrosion cracking in hot, halide salt solutions. The purpose of this paper is to characterize the performance of the Ni‐Cr‐Mo alloys in several key chemicals, using iso‐corrosion diagrams. These indicate the expected corrosion rates over wide ranges of concentration and temperature. Furthermore, the differences between individual Ni‐Cr‐Mo alloys, and their behavior relative to the stainless steels are defined. The data indicate benefits of both a high chromium content and a copper addition, as used in Hastelloy® C‐2000® alloy.
Effect of (R+, X–) salts addition on nickel corrosion in 1M sulfuric acid medium
Authors: Said F. , Souissi N. , Dermaj A. , Hajjaji N. , Triki E. , Srhiri A.
Published: September 2005

We used the electrochemical techniques to study the effect of the addition of four salts, K+,Cl−, K+,Br−, K+,I− and C8H17Ph3P+,I−, on the corrosion behaviour of nickel when submitted to 1M sulphuric acid medium. After one hour of immersion time, we noted an acceleration of nickel corrosion process after the addition of K+,Cl− and K+,Br− in the 1M H2SO4 electrolyte. K+,I− exhibited an inhibition of the anodic Ni corrosion process whereas the phosphonium iodine (R+,I−) acts simultaneously on both processes: it is a mixed inhibitor. Such result is due to the adsorption of the alkyl group C8H17 which limited oxygen diffusion.

EIS characterization of Ni exhibited surfaces after iodine salts addition allowed us simulating the resulting interfaces by electrical equivalent circuits. We concluded that (K+,I−) addition decreased the material corrosion rate without changing the alteration mechanism. That result is due to the formation of NiI at the electrode surface. On the other hand, phosphonium iodine addition modifies the interface behaviour. In fact, the alkyl part of the organic iodine adsorbs at the surface preserving it against the corrosive action of the sulfuric acid.
The study of the La(NO;3)3 inhibition on X70 pipeline steel in 3.0(wt.%) NaCl solution
Authors: Zhang L.J. , Zhang Z. , Zhang J.Q. , Cao C.N.
Published: September 2005

Lanthanum nitrate has been investigated as corrosion inhibitor of X70 pipeline steel in 3.0 (wt.%) NaCl solution using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in conjunction with scanning electron microscopy (SEM) and energy dispersive X‐ray detector (EDX) techniques. The results showed that La(NO3)3 belonged to the film‐formed mixed inhibitors, which can form a compact network over the whole surface of X70 pipeline steel. The inhibition effect of La(NO3)3 on X70 steel reinforced with the increase of the concentration itself. The EDX analysis showed that lanthanum ions were found to participate in the network film formed on the sample surface.
Evaluation of a biocide effect upon microbiologically influenced corrosion of mild steel
Authors: Hernández Gayosso M. J. , Zavala Olivares G. , Ruiz Ordaz N. , García Esquivel R.
Published: September 2005

The microbiologically influenced corrosion (MIC) is a very dangerous process, which affects the oil industry. The activity and microorganisms' growth at the pipelines steel cause surface modifications, which can induce a more complex corrosion process. The biocide evaluation for the MIC decrease has been normally based upon microbiological tests, and just a few references mention alternating methods which can be used as criteria for their evaluation. In this work, a commercial biocide was tested, using different electrochemical laboratory techniques, to determine its effect upon a biofilm generating bacteria consortium.

Using microbiological techniques, the biocide lethal concentration was determined, and a concentration of 200 ppm was used to kill completely the consortium population in both, plancktonic and sessile parts. The electrochemical techniques: Polarisation Resistance (PR) and Electrochemical Impedance Spectroscopy (EIS), allowed describing the corrosion process associated to the microbial consortium and the biocide effect upon it.
An ultra‐sulfur Hastelloy alloy C‐4
Authors: Xiaobo L. , Youqing X. , Yaoxiao Z.
Published: September 2005

The effect of sulfur on solidification‐segregation and corrosion resistant properties of Hastelloy C‐4 corrosion‐resistant alloy was studied. It was found that strict controlling the content of sulfur can reduce the width and temperature interval of the solid‐liquid biphase region and the segregation degree of the alloy, resulting in a higher corrosion resistance. An improved low segregation Hastelloy C‐4 corrosion resistant alloy was developed.
Binding and Sulfonation of Poly(acrylic acid) on Iron Oxide Nanoparticles: a Novel, Magnetic, Strong Acid Cation Nano‐Adsorbent
Authors: Mak Sou‐Yee , Chen Dong‐Hwang
Published: September 2005

Summary: A novel, magnetic, strong acid cation nano‐adsorbent has been developed by the covalent binding of poly(acrylic acid) on the surface of Fe3O4 nanoparticles followed by sulfonation using sulfanilic acid via carbodiimide activation. The nano‐absorbent can be easily recovered or manipulated with an external magnetic field and shows a good capacity for the rapid and efficient adsorption of multivalent metal cations from aqueous solutions.

An illustration for the binding and sulfonation of PAA on Fe3O4 nanoparticles to produce a magnetic, strong acid cation nano‐adsorbent.

magnified image

An illustration for the binding and sulfonation of PAA on Fe3O4 nanoparticles to produce a magnetic, strong acid cation nano‐adsorbent.