bluuebunny/crossref_metadata_2025 huggingface dataset:
Content independence in multimedia databases
Authors: de Vries Arjen P.
Published: November 2004

A database management system is a general‐purpose software system that facilitates the processes of defining, constructing, and manipulating databases for various applications. This article investigates the role of data management in multimedia digital libraries, and its implications for the design of database management systems. The notions of content abstraction and content independence are introduced, which clearly expose the unique challenges (for database architecture) of applications involving multimedia search. A blueprint of a new class of database technology is proposed, which supports the basic functionality for the management of both content and structure of multimedia objects.
Evaluating image browsers using structured annotation
Authors: Müller Wolfgang , Marchand‐Maillet Stéphane , Müller Henning , Squire David McG. , Pun Thierry
Published: November 2004

In this article we address the problem of benchmarking image browsers. Image browsers are systems that help the user in finding an image from scratch, as opposed to query by example (QBE), where an example image is needed. The existence of different search paradigms for image browsers makes it difficult to compare image browsers. Currently, the only admissible way of evaluation is by conducting large‐scale user studies. This makes it difficult to use such an evaluation as a tool for improving browsing systems. As a solution, we propose an automatic image browser benchmark that uses structured text annotation of the image collection for the simulation of the user's needs. We apply such a benchmark on an example system.
The effect of extrinsic motivation on user behavior in a collaborative information finding system
Authors: Shapira Bracha , Kantor Paul B. , Melamed Benjamin
Published: November 2004

In collaborative information finding systems, evaluations provided by users assist other users with similar needs. This article examines the problem of getting users to provide evaluations, thus overcoming the so‐called “free‐riding” behavior of users. Free riders are those who use the information provided by others without contributing evaluations of their own. This article reports on an experiment conducted using the “AntWorld,” system, a collaborative information finding system for the Internet, to explore the effect of added motivation on users' behavior. The findings suggest that for the system to be effective, users must be motivated either by the environment, or by incentives within the system. The findings suggest that relatively inexpensive extrinsic motivators can produce modest but significant increases in cooperative behavior.
Quantitative assessment of image retrieval effectiveness
Authors: Smith John R.
Published: November 2004

Content‐based retrieval (CBR) promises to greatly improve capabilities for searching for images based on semantic features and visual appearance. However, developing a framework for evaluating image retrieval effectiveness remains a significant challenge. Difficulties include determining how matching at different description levels affects relevance, designing meaningful benchmark queries of large image collections, and developing suitable quantitative metrics for measuring retrieval effectiveness. This article studies the problems of developing a framework and testbed for quantitative assessment of image retrieval effectiveness. In order to better harness the extensive research on CBR and improve capabilities of image retrieval systems, this article advocates the establishment of common image retrieval testbeds consisting of standardized image collections, benchmark queries, relevance assessments, and quantitative evaluation methods.
Extremely low frequency‐modulated static magnetic fields to treat cancer: A pilot study on patients with advanced neoplasm to assess safety and acute toxicity
Authors: Ronchetto Flavio , Barone Domenico , Cintorino Marcella , Berardelli Michele , Lissolo Silvana , Orlassino Renzo , Ossola Piero , Tofani Santi
Published: November 2004

Results of a toxicity pilot human study approved by the competent ethical Committee are reported. Eleven patients with heavily pre‐treated advanced cancer were enrolled in a pilot study with different schedules of time exposure to static magnetic fields (MF), amplitude modulated by ELF. An area including the neck, thoracic and abdomen was MF exposed daily, 5 days/week for 4 weeks according to two different schedules: 20 min daily (4 patients) and 70 min daily (7 patients). ECOG performance status was 1 (2 patients), 2 (8 patients), 3 (1 patient). Toxicity was assessed according to WHO criteria. ECG, Chest X‐ray, physical examination, blood cell count and complete blood chemistry were performed before and at the end of the treatment. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) elevation (grade 2 toxicity) in 1 patient and microscopic urinary abnormalities in 5 patients were the only negative effects observed. We conclude that MF can be safely administrated according to the MF exposure schedules. Bioelectromagnetics 25:563–571, 2004. © 2004 Wiley‐Liss, Inc.
Fluorescence‐based sensing system for copper using genetically engineered living yeast cells
Authors: Shetty Ranjit S. , Deo Sapna K. , Liu Yue , Daunert Sylvia
Published: November 2004

A whole cell‐based optical sensing system for copper was developed based onSaccharomyces cerevisiaecells harboring plasmid pYEX‐GFPuv. The basis of this system was the ability of the transcriptional activator protein Ace1 present inS. cerevisiaeto control the expression of the reporter protein, GFPuv. When copper ions are present in the sample, the Ace1 protein activates thecup1promoter located upstream from thegfpuvgene in plasmid pYEX‐GFPuv, thus inducing the production of GFPuv. The concentration of copper ions in the sample can then be related to the GFPuv expressed in the yeast. The amount of GFPuv produced in the system was determined by monitoring the fluorescence emitted at 507 nm after excitation at 397 nm. This system can detect copper at concentrations as low as 5 × 10−7M, and is selective for copper over a variety of metal ions, with the exception of silver. The applicability of this sensing system to different analytical platforms and in real samples is demonstrated. © 2004 Wiley Periodicals, Inc.
Emergency ligation of the brachial artery for complications of vascular access
Authors: Tan Y-M , Tan S-G
Published: November 2004

Safe, if there is no alternative
Projection and local interneurons in the sixth abdominal ganglion of the sand crab Emerita analoga (Hippidae)
Authors: Paul Dorothy Hayman
Published: November 2004

Hippid crabs are adapted for life in the surf zone of exposed sandy beaches, and their tailfan differs from the tailfans of other crustaceans with respect to morphology and motor control and in having nonspiking stretch receptors (NSR). To investigate how these crabs' mechanosensory systems are adapted to this turbulent environment, I used axonal back‐filling and intracellular recording with dye‐filled microelectrodes to describe afferent projections from the telson and morphologies and physiological responses of intersegmental and local neurons in abdominal ganglion 6 (A6) in Emerita analoga, then compared them with descriptions of corresponding neurons in A6 of crayfish. The density of afferent terminals and the proportion of projection neuron somata is lower in anterior A6 of E. analoga than in crayfish, perhaps correlated with a reduction in hydrodynamic setae. Many interneurons responded to afferent nerve stimulation and displayed activity correlated with levels of A6 motor output. NSR stretch depolarizes unilateral local neurons and terminals of axons entering A6 from the connective and hyperpolarizes bilateral local and projection neurons. The timing and duration of this inhibition would suppress mechanosensory input from the telson during uropod beating (homologue of crayfish's nongiant tail‐flipping). Suppression of reafference during uropod beating may have been pivotal for evolution of hippids' ability to move rapidly across the water‐sand interface in the slosh zone of sandy beaches. Homologies between A6 neurons in E. analoga and crayfish, suggested by morphological and physiological similarities, indicate that the NSRs connect to a neuronal network regulating exteroceptive input that was inherited from their tail‐flipping ancestors. J. Comp. Neurol. 480:310–329, 2004. © 2004 Wiley‐Liss, Inc.
Expression of the vesicular glutamate transporters during development indicates the widespread corelease of multiple neurotransmitters
Authors: Boulland Jean‐Luc , Qureshi Tayyaba , Seal Rebecca P. , Rafiki Amina , Gundersen Vidar , Bergersen Linda H. , Fremeau Robert T. , Edwards Robert H. , Storm‐Mathisen Jon , Chaudhry Farrukh A.
Published: November 2004

Three closely related proteins transport glutamate into synaptic vesicles for release by exocytosis. Complementary patterns of expression in glutamatergic terminals have been reported for VGLUT1 and VGLUT2. VGLUT3 shows expression by many cells not considered to be glutamatergic. Here we describe the changes in VGLUT expression that occur during development. VGLUT1 expression increases gradually after birth and eventually predominates over the other isoforms in telencephalic regions. Expressed at high levels shortly after birth, VGLUT2 declines with age in multiple regions, in the cerebellum by 14‐fold. In contrast, Coexpression of the two isoforms occurs transiently during development as well as permanently in a restricted subset of glutamatergic terminals in the adult. VGLUT3 is transiently expressed at high levels by select neuronal populations, including terminals in the cerebellar nuclei, scattered neurons in the cortex, and progenitor‐like cells, implicating exocytotic glutamate release in morphogenesis and development. VGLUT3 also colocalizes extensively during development with the neuronal vesicular monoamine transporter VMAT2, with the vesicular acetylcholine transporter VAChT, and with the vesicular γ‐aminobutyric acid transporter VGAT. Such coexpression occurs particularly at some specific developmental stages and is restricted to certain sets of cells. In skeletal muscle, VGLUT3 localizes to granular organelles in the axon terminal as well as in the muscle sarcoplasm. The results suggest novel mechanisms and roles for regulated transmitter release. J. Comp. Neurol. 480:264–280, 2004. © 2004 Wiley‐Liss, Inc.
Empirical Treatment of the Inductive and Dispersive Components of Solute−Solvent Interactions: The Solvent Polarizability (SP) Scale
Authors: Catalán Javier , Hopf Henning
Published: November 2004

By using 3,20‐di‐tert‐butyl‐2,2,21,21‐tetramethyl‐3,5,7,9,11, 13,15,17,19‐docosanonaene (ttbP9) as a probe, the inductive and dispersive interactions of solvents were empirically evaluated for the first time. This probe exhibits a very strong first electronic transition with a marked vibronic structure that is very well resolved from the second electronic transition. One hundred solvents were used to construct a solvent polarizability (SP) scale ranging from zero for the gas phase (i.e. the absence of solvent) to unity for carbon disulfide. The probe was found to exhibit an ideal spectroscopic behaviour towards a variety of polar, acidic and basic solvents. The polarizability scale provides an accurate description of the solvatochromism of such interesting apolar chromophores as anthracene, molecular oxygen, and C60 among a wider variety of solvents spanning very broad ranges of polarity, acidity and basicity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Probing Gelation at the Molecular Level: Head‐to‐Tail Hydrogen‐Bonded Self‐Assembly of an Inositol‐Based Organogelator
Authors: Sureshan Kana M. , Yamaguchi Kentaro , Sei Yoshihisa , Watanabe Yutaka
Published: November 2004

A simple cyclitol derivative has been found to gelate many low‐polar solvents. A detailed molecular level investigation demonstrated that the intermolecular head‐to‐tail hydrogen bond plays a key role in the self‐assembly of the monomers to generate supramolecular polymeric fibres. Such self‐assembled oligomeric forms could be detected even in a competing protic solvent. Control experiments further established that optimally oriented hydroxy groups and chirality are the crucial factors for the gelation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
2,3,4‐Triphenyl‐3‐azabicyclo[3.2.0]hepta‐1,4‐diene − Facile Ring‐Opening by Electrophiles and Novel Reactions with Dimethyl Acetylenedicarboxylate
Authors: Matsumoto Kiyoshi , Goto Sadahito , Hayashi Naoto , Iida Hirokazu , Uchida Takane , Kakehi Akikazu
Published: November 2004

A 3‐azabicyclo[3.2.0]hepta‐1,4‐diene with no substituent in the cyclobutene moiety has been prepared for the first time; it undergoes extremely facile electrophilic attack at the β‐position to give the ring‐opened product, probably by a retro‐Friedel−Crafts process. The title compound also undergoes a novel reaction with dimethyl acetylenedicarboxylate to afford the azepine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Substrate‐Specific Amidation of Carboxylic Acids in a Liquid−Liquid Two‐Phase System Using Cyclodextrins as Inverse Phase‐Transfer Catalysts
Authors: Kunishima Munetaka , Watanabe Yasunobu , Terao Keiji , Tani Shohei
Published: November 2004

A novel system for substrate‐specific activation of carboxylic acids leading to the formation of carboxamides has been developed in our laboratory. A combination of a water‐soluble dehydrocondensing agent, 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride (DMT‐MM), and an inverse phase‐transfer catalyst (IPTC) (hydroxypropyl)cyclodextrin (HP‐β‐CD), in a water/ether biphasic solvent system was found to be most effective. A lipophilic carboxylic acid with a strong affinity for the cavity of HP‐β‐CD can be selectively transferred to the aqueous phase and predominantly reacts with DMT‐MM, dissolving in the aqueous phase. The substrate specificity was similar to that observed with a complex artificial enzyme based on CD. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An Improved Stereoselective Synthesis of L‐Alanosine
Authors: Strazzolini Paolo , Dall’Arche Maria Grazia , Zossi Maura , Pavsler Andrea
Published: November 2004

An improved, stereoselective synthesis of the natural, non‐proteogenic amino acid L‐alanosine has been developed, starting from the readily available and cheap substrate L‐serine, in six steps and 49% overall yield. The process is very efficient, is suitable for large‐scale production, and affords L‐alanosine with properties comparable with those of the natural substance. In addition, the structural assignment concerning some previously reported synthetic alkylated derivatives of the natural amino acid has been definitively confirmed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An Approach to Simple Reaction Control for Auto‐thermal Fuel‐reforming Systems
Authors: Komachiya M. , Hiyama K. , Higashiyama K. , Okano T. , Yatabe H. , Imada N. , Kaku H.
Published: November 2004

A simple approach to reaction control for auto‐thermal fuel‐reforming systems was proposed and examined. The amount of air supplied to the fuel‐reforming system was chosen as the variable in the feedback (closed‐loop) control operation, and simply by varying the amount of air supplied, it was attempted to control and stabilize the temperature of the auto‐thermal reforming reaction. The amounts of other fuels and water were chosen from pre‐determined values by open‐loop operation. Since the feedback operation was limited to the air‐supply mechanism, it was expected that both the hardware structure of the system and its software configurations could be significantly simplified. The applicability of this simple feedback control operation was confirmed experimentally by using a methanol reformer of the direct‐injection type.
Fuel Cell Vehicles at General Motors
Authors: v. Helmolt R.
Published: November 2004

An overview of GM/Opel's hydrogen fuel cell vehicles is presented. Three vehicle generations have been put into operation within the past four years, and valuable practical experience has been gained. GM/Opel's development targets are today shifting from pure performance optimisation to more varied aims, including reliability and durability considerations. Increased attention is also being paid to the fuel storage factor, which is a major issue for hydrogen cars.
Novel Polymer Electrolyte Membranes for Automotive Applications – Requirements and Benefits
Authors: Wieser C.
Published: November 2004

During the past few years, the feasibility of using polymer electrolyte fuel cells in automotive power trains at an impressive performance level has been proven repeatedly. However, current fuel cell stacks are still largely based on decade‐old polymer electrolyte membrane technology thus limiting performance, durability, reliability, and cost of the fuel cell systems. The major challenge for membrane R&D constitutes the demand for polymer electrolytes that allow for system operation at higher temperatures and lower water management requirements without increased conduction losses. None the less, demanding automotive requirements will not compromise on other properties such as mechanical and chemical stability and gas permeability.
Chloride free Pt‐ and PtRu‐ Nanoparticles Stabilised by “Armand's Ligand” as Precursors for Fuel Cell Catalysts
Authors: Bönnemann H. , Brinkmann R. , Kinge S. , Ely T. O. , Armand M.
Published: November 2004

Chloride residues on the surface of fuel cell catalysts are known to decrease the catalytic activity, especially for O2 reduction. Using Armand's ligand, which contains the chloride free DCTA anion, for the colloidal stabilisation of nanoscopic Pt and PtRu catalysts precursors (< 2 nm size) leads to PEMFC and DMFC catalysts with improved activity compared to commercial E‐TEK catalysts as evidenced by both methanol oxidation and CO‐stripping voltametric studies.
Prospects for Alkaline Anion‐Exchange Membranes in Low Temperature Fuel Cells
Authors: Varcoe J. R. , Slade R. C. T.
Published: November 2004

This article introduces the radical approach of applying alkaline anion‐exchange membranes (AAEMs) to meet the current challenges with regards to direct methanol fuel cells (DMFCs). A review of the literature is presented with regards to the testing of fuel cells with alkaline membranes (fuelled with hydrogen or methanol) and also to candidate alkaline anion‐exchange membranes for such an application. A brief review of the directly related patent literature is also included. Current and future research challenges are identified along with potential strategies to overcome them. Finally, the advantages and challenges with the direct electrochemical oxidation of alternative fuels are discussed, along with how the application of alkaline membranes in such fuel cells may assist in improving performance and fuel efficiency.
Simplifying head and neck microvascular reconstruction
Authors: Rosenthal Eben , Carroll William , Dobbs Mathew , Scott Magnuson J. , Wax Mark , Peters Glenn
Published: November 2004

Background.

Free‐tissue transfer has become the preferred method of head and neck reconstruction but is a technique that is considered to use excessive hospital resources.

Methods.

This study is a retrospective review of 125 consecutive free flaps in 117 patients over a 16‐month period at a tertiary care university hospital.

Results.

Defects of the oral cavity/oropharynx (60%), midface (9%), hypopharynx (15%), or cervical and facial skin (16%) were reconstructed from three donor sites: forearm (70%), rectus (11%), and fibula (19%). Microvascular anastomoses were performed with a continuous suture technique or an anastomotic coupling device for end‐to‐end venous anastomoses. A single vein was anastomosed in 97% of tissue transfers. There were five flaps (4%) requiring exploration for vascular compromise, and the overall success rate was 97.6%. The major complication rate was 13%. Mean hospital stay was 7 days for all patients and 5 days for those with cutaneous defects. Combined ablative and reconstructive operative times were 6 hours 42 minutes, 7 hours 40 minutes, and 8 hours 32 minutes for forearm, rectus, and fibular free grafts, respectively. A subset of this patient series with oral cavity and oropharynx defects (76 patients; 58%) available for follow‐up (74 patients) was assessed for deglutition. Forty‐three patients (58%) had a regular diet, 22 patients (30%) had a limited diet or required supplemental tube feedings, and nine patients (12%) were dependent on tube feedings with a severely limited diet.

Conclusions.

This series suggests that most head and neck defects can be reconstructed by use of a simplified microvascular technique and a limited number of donor sites. Analysis of operative times and length of stay suggest improved efficiency with this approach to microvascular reconstruction. Complications and functional results are comparable to previously published results. © 2004 Wiley Periodicals, Inc. Head Neck 26: 930–936, 2004
Postoperative irradiation for squamous cell carcinoma of the oral cavity: 35‐year experience
Authors: Hinerman Russell W. , Mendenhall William M. , Morris Christopher G. , Amdur Robert J. , Werning John W. , Villaret Douglas B.
Published: November 2004

Background.

The purpose of this study was to analyze factors influencing outcome in patients who received postoperative irradiation for advanced squamous cell carcinoma of the oral cavity.

Methods.

Between October 1964 and November 2000, 226 patients with 230 previously untreated primary invasive squamous cell carcinomas of the oral cavity were treated postoperatively with continuous‐course external beam irradiation. All patients had a minimum follow‐up of 2 years (analysis, November 2002). No patient was lost to follow‐up.

Results.

The 5‐year actuarial rates of locoregional control by pathologic American Joint Committee on Cancer stage were: stage I, 100%; stage II, 84%; stage III, 78%; and stage IV, 66%. Recurrence of cancer above the clavicles developed in 55 patients (24%). In multivariate analysis of locoregional control, positive margins, vascular invasion, perineural invasion, extracapsular extension, and T classification remained significant.

Conclusions.

This article provides additional data defining relatively favorable and unfavorable groups of patients in the postoperative setting. Dose recommendations are re‐examined and selectively increased for high‐risk patients. © 2004 Wiley Periodicals, Inc.Head Neck26:984–994, 2004
FGF‐2 enhances the mitotic and chondrogenic potentials of human adult bone marrow‐derived mesenchymal stem cells
Authors: Solchaga Luis A. , Penick Kitsie , Porter John D. , Goldberg Victor M. , Caplan Arnold I. , Welter Jean F.
Published: November 2004

Human mesenchymal stem cells (hMSCs) expanded with and without fibroblast growth factor (FGF) supplementation were compared with respect to their proliferation rate, ability to differentiate along the chondrogenic pathway in vitro, and their gene expression profiles. hMSCs expanded in FGF‐supplemented medium were smaller and proliferated more rapidly than hMSCs expanded in control conditions. Chondrogenic cultures made with FGF‐treated cells were larger and contain more proteoglycan than those made with control cells. Furthermore, aggregates of FGF‐treated cells lacked the collagen type I‐positive and collagen type II‐negative outer layer characteristic of aggregates of control cells. A total of 358 unique transcripts were differentially expressed in FGF‐treated hMSCs. Of these, 150 were upregulated and 208 downregulated. Seventeen percent of these genes affect proliferation. Known genes associated with cellular signaling functions comprised the largest percentage (∼20%) of differentially expressed transcripts. Eighty percent of differentially expressed extracellular matrix‐related genes were downregulated. The present findings that FGF‐2 enhances proliferation and differentiation of hMSCs adds to a growing body of evidence that cytokines modulate the differentiation potential and, perhaps, the multipotentiality of adult stem cells. With the generation of gene expression profiles of FGF‐treated and control cells we have taken the first steps in the elucidation of the molecular mechanism(s) behind these phenomena. © 2004 Wiley‐Liss, Inc.
Cholesterol depletion perturbs calcium handling by rat submandibular glands
Authors: Garcia‐Marcos M. , Tandel S. , Pochet S. , Genin J. , De Lorenzi M. , Gomez F. , Kumps A. , Marino A. , Dehaye J.P.
Published: November 2004

The sensitivity to cholesterol depletion of calcium handling by rat submandibular glands was investigated. The glands were digested with collagenase. After homogenization, the lysate was extracted at 4°C with 0.5% Triton X‐100 and the extract was submitted to an ultracentrifugation in a sucrose discontinuous gradient. A population of detergent‐resistant membranes (DRM) was collected at the 5%–35% interface. The DRM had a higher content of cholesterol, saturated and long‐chain fatty acids. Caveolin‐1 and αq/11 were located in these membranes. They were more ordered than vesicles from total cellular lysate as determined by anisotropy measurement. They disappeared after cholesterol extraction with methyl‐β‐cyclodextrin (MCD). Exposure of the cellular suspension with MCD nearly abolished the response to carbachol, epinephrine, and substance P and inhibited the activation of phospholipase C (PLC) by these agonists and by sodium fluoride. MCD did not affect the mobilization of intracellular pools of calcium by thapsigargin. It increased the uptake of extracellular calcium or barium and did not inhibit the uptake of calcium after depletion of the intracellular stores of this ion. From these results, it is concluded that Triton X‐100 can extract a fraction of membrane resistant to detergents. Treatment of the cells with MCD disrupts these membranes. The coupling between the heterotrimeric GTP‐binding protein Gq/11 and poly‐phosphoinositide‐specific PLC is affected by disruption of these membrane fractions. At the opposite, the store‐operated calcium channel (SOCC) is not affected by DRM‐disruption. © 2004 Wiley‐Liss, Inc.
Expression of the urokinase receptor regulates focal adhesion assembly and cell migration in adenoid cystic carcinoma cells
Authors: Abu‐Ali Samah , Sugiura Tsuyoshi , Takahashi Miho , Shiratsuchi Toru , Ikari Tatsuya , Seki Katsuhiro , Hiraki Akimitsu , Matsuki Ryousuke , Shirasuna Kanemitsu
Published: November 2004

Adenoid cystic carcinoma (AdCC) cell lines (ACCS and ACCT) showed higher migration responses and adhesion to the extracellular matrix (ECM), especially types I and IV collagen, than did the oral squamous cell carcinoma (SCC) lines (NA and TF). The response to collagens was largely and exclusively inhibited by anti‐α2 integrin antibody. Moreover, AdCC cell lines expressed higher surface levels of urokinase‐type plasminogen activator receptor (uPAR) than did SCC cell lines. When AdCC cells were plated on collagen, the surface level of uPAR was increased, and numerous focal adhesions consisting of uPAR, vinculin, and paxillin were assembled; whereas collagen‐stimulated SCC cell counterparts or AdCC cells plated on other types of ECM, such as fibronectin, failed to assemble such definite focal adhesions. In order to elucidate the association of uPAR with collagen‐induced events, an ACCS‐AS cell line transfected with a vector expressing antisense uPAR RNA was established and shown to have reduced uPAR (about 10% that of parental ACCS at both the protein and mRNA levels). ACCS‐AS showed a strong reduction of collagen‐stimulated migration and focal adhesion assembly of α2 integrin, vinculin, and paxillin. These findings suggest that AdCC has a proclivity for migrating to types I and IV collagens due to the overexpression of uPAR, which plays a key role in focal adhesion assembly and migration. © 2004 Wiley‐Liss, Inc.
Mitochondrial tissue specificity of substrates utilization in rat cardiac and skeletal muscles
Authors: Ponsot E. , Zoll J. , N'Guessan B. , Ribera F. , Lampert E. , Richard R. , Veksler V. , Ventura‐Clapier R. , Mettauer B.
Published: November 2004

As energetic metabolism is crucial for muscles, they develop different adaptations to respond to fluctuating demand among muscle types. Whereas quantitative characteristics are known, no study described simultaneously quantitative and qualitative differences among muscle types in terms of substrates utilization patterns. This study thus defined the pattern of substrates preferential utilization by mitochondria from glycolytic gastrocnemius (GAS) and oxidative soleus (SOL) skeletal muscles and from heart left ventrical (LV) in rats. We measured in situ, ADP (2 mM)‐stimulated, mitochondrial respiration rates from skinned fibers in presence of increasing concentrations of pyruvate (Pyr) + malate (Mal), palmitoyl‐carnitine (Palm‐C) + Mal, glutamate (Glut) + Mal, glycerol‐3‐phosphate (G3‐P), lactate (Lact) + Mal. Because the fibers oxygen uptake (Vs) followed Michaelis–Menten kinetics in function of substrates level we determined the Vs and Km, representing maximal oxidative capacity and the mitochondrial sensibility for each substrate, respectively. Vs were in the order GAS < SOL < LV for Pyr, Glu, and Palm‐C substrates, whereas in the order SOL = LV < GAS with G3‐P. Moreover, the relative capacity to oxidize Palm‐C is extremely higher in LV than in SOL. Vs was not stimulated by the Lact substrate. The Km was equal for Pyr among muscles, but much lower for G3‐P in GAS and lower for Palm‐C in LV. These results demonstrate qualitative mitochondrial tissue specificity for metabolic pathways. Mitochondria of glycolytic muscle fibers are well adapted to play a central role for maintaining a satisfactory cytosolic redox state in these fibers, whereas mitochondria of LV developed important capacities to use fatty acids. © 2004 Wiley‐Liss, Inc.
Transcriptional regulation of thioredoxin reductase 1 expression by cadmium in vascular endothelial cells: Role of NF‐E2‐related factor‐2
Authors: Sakurai Atsuko , Nishimoto Michie , Himeno Seiichiro , Imura Nobumasa , Tsujimoto Masafumi , Kunimoto Manabu , Hara Shuntaro
Published: November 2004

Thioredoxin reductase (TrxR) is a selenoprotein that catalyzes the reduction of the active site disulfide of thioredoxin (Trx), which regulates the redox status of the cells. In the present study, we found that TrxR1, one of the three TrxR isozymes, was induced by cadmium as well as tumor necrosis factor α (TNFα) in bovine arterial endothelial cells (BAEC), and investigated the mechanism of cadmium‐induced TrxR1 expression. We here showed that cadmium, differently from TNFα, enhanced the promoter activity of the 5′‐flanking region of human TrxR1 gene (nucleotides −1692 to +49). Deletion and site‐directed mutation of antioxidant responsive element (ARE) (nucleotides −62 to −48) in this region abolished the response to cadmium. Overexpression of NF‐E2‐related factor‐2 (Nrf2) augmented the TrxR1 promoter activity. In contrast, overexpression of the dominant negative mutant of Nrf2 suppressed cadmium‐induced activation of TrxR1 promoter through the ARE. Chromatin immunoprecipitation (ChIP) assays showed that anti‐Nrf2 antibody precipitated ARE from the chromatin of the cadmium‐treated cells. These results indicated that cadmium‐induced TrxR1 gene expression is mediated by the activation of Nrf2 transcription factor and its binding to ARE in the TrxR1 gene promoter. We further found that in addition to cadmium, the activators of Nrf2, such as diethyl maleate (DEM) and arsenite, induced both TrxR1 and Trx gene expression in BAEC. Nrf2 might play an important role in the regulation of the cellular Trx system consisting of Trx and TrxR. © 2004 Wiley‐Liss, Inc.
Hedgehog signaling in normal urothelial cells and in urothelial carcinoma cell lines
Authors: Thievessen Ingo , Wolter Marietta , Prior Andrea , Seifert Hans‐Helge , Schulz Wolfgang A.
Published: November 2004

Constitutive activation of hedgehog signaling, often caused byPTCH1inactivation and leading to inappropriate activation of GLI target genes, is crucial for the development of several human tumors including basal cell carcinoma of the skin and medulloblastoma. ThePTCH1gene at 9q22 is also considered as a candidate tumor suppressor in transitional cell carcinoma (TCC), of which >50% show LOH in this region. However, only rare mutations have been found inPTCH1. We have therefore investigated GLI‐dependent promoter activity and expression of hedgehog pathway components in TCC cell lines and proliferating normal urothelial cells. Normal urothelial cells cultured in serum‐free medium, but not TCC lines exhibited low, but significant promoter activity under standard growth conditions. Accordingly, GLI1‐3 andPTCH1mRNAs were expressed at moderate levels, and sonic hedgehog (SHH) mRNA expression was low to undetectable. In co‐transfection experiments GLI1 increased promoter activity significantly in one TCC line and further in normal urothelial cells, but less strongly in other TCC lines. Expression patterns of GLI factor mRNAs did not correlate with inducibility. No significant effects of SHH or cyclopamine on proliferation were observed, ruling out autocrine effects. However, SHH induced GLI‐dependent promoter activity in normal urothelial cells. Taken together, our data suggest that the hedgehog pathway is weakly active in normal adult urothelial cells and of limited importance in TCC. © 2004 Wiley‐Liss, Inc.
Requirement of protein phosphatase 2A for recruitment of IQGAP1 to Rac‐bound β1 integrin
Authors: Suzuki Katsuo , Chikamatsu Yasuhiro , Takahashi Kazuhide
Published: November 2004

Serine/threonine protein phosphatase (PP) 2A is thought to dephosphorylate phosphorylated β1 integrin to link with actin filaments (F‐actin). However, whether PP2A participates in the regulation of F‐actin assembly to which β1 integrin is anchored is unclear. We report here that the core enzyme of PP2A (PP2A‐AC), consisting of the regulatory subunit A (PP2A‐A) and the catalytic subunit C (PP2A‐C), forms a complex with β1 integrin, a small GTPase Rac, and its effector IQGAP1 in non‐malignant human mammary epithelial (HME) cells. Treatment of HME cells with okadaic acid (OA), an inhibitor of PP2A, caused cell rounding, reduction in F‐actin assembly that links with β1 integrin, and dissociation of IQGAP1‐bound PP2A‐AC from Rac‐β1 integrin. The dissociation of IQGAP1‐PP2A‐AC was accompanied by loss of F‐actin gelating activity of Rac‐β1 integrin. In breast cancer MCF‐7 cells, which possess PP2A‐C but lack PP2A‐A, IQGAP1 was not associated with Rac‐β1 integrin but with PP2A‐C, with no distinct F‐actin assembly that linked to Rac‐β1 integrin even before treatment with OA. We therefore propose that PP2A, especially PP2A‐A, functions to maintain F‐actin assembly to which β1 integrin is anchored by recruitment of IQGAP1 to Rac‐β1 integrin. © 2004 Wiley‐Liss, Inc.
Birds have dinosaur wings: The molecular evidence
Authors: Vargas Alexander O. , Fallon John F.
Published: November 2004

Within developmental biology, the digits of the wing of birds are considered on embryological grounds to be digits 2, 3 and 4. In contrast, within paleontology, wing digits are named 1, 2, 3 as a result of phylogenetic analysis of fossil taxa indicating that birds descended from theropod dinosaurs that had lost digits 4 and 5. It has been argued that the development of the wing does not support the conclusion that birds are theropods, and that birds must have descended from ancestors that had lost digits 1 and 5. Here we use highly conserved gene expression patterns in the developing limbs of mouse and chicken, including the chicken talpid2mutant and polydactylous Silkie breed (Silkie mutant), to aid the assessment of digital identity in the wing. Digit 1 in developing limbs does not express Hoxd12, but expresses Hoxd13. All other digits express both Hoxd12and Hoxd13. We found this signature expression pattern identifies the anteriormost digit of the wing as digit 1, in accordance with the hypothesis these digits are 1, 2 and 3, as in theropod dinosaurs. Our evidence contradicts the long‐standing argument that the development of the wing does not support the hypothesis that birds are living dinosaurs. J. Exp. Zool. (Mol. Dev. Evol.) 304:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Low‐pH‐sensitive poly(ethylene glycol) (PEG)‐stabilized plasmid nanolipoparticles: effects of PEG chain length, lipid composition and assembly conditions on gene delivery
Authors: Li Weijun , Huang Zhaohua , MacKay J. Andrew , Grube Stefan , Szoka Francis C.
Published: November 2004

Background

We have studied the effects of the poly(ethylene glycol) (PEG) chain length and acyl chain composition on the pH‐sensitivity of acid‐labile PEG‐diorthoester (POD) lipids. The optimal conditions are described for preparation of DNA plasmid encapsulated POD nanolipoparticles (NLPs) which mediate high gene delivery activity in vitro with moderate cytotoxicity.

Methods and Results

A series of POD lipids with various PEG chain lengths (750, 2000, and 5000 Da) or acyl chains (distearoyl 18 : 0 or dioleoyl 18 : 1) were incorporated into DNA containing NLPs or model liposomes as a stealth and bioresponsive component. We investigated the collapse kinetics of the POD‐stabilized liposomes when the PEG chain length was changed. We optimized a detergent dialysis method to encapsulate plasmid DNA into NLPs prepared from a mixture of the various POD lipids, cationic lipid and phosphatidylethanolamine lipid. A critical concentration (28 mM) of n‐octyl‐β‐D‐glucopyranoside (OG) enabled high encapsulation of DNA plasmid into 100 nm particles with a neutral surface charge. The POD NLPs are stable at pH 8.5 but rapidly collapse (∼10 min) into aggregates at pH 5.0. In the detergent solution there is a metastable DNA‐lipid intermediate that evolves into a stable NLP if the detergent is removed shortly after adding DNA to the lipid‐detergent mixture. The rank order of transfection activity from NLPs containing PEG‐lipid was POD 750 > POD 5000 = POD 2000 > non‐pH‐sensitive PEG‐lipid. The particle size stability was in the reverse order. Binding of the NLPs to cells reached a maximum level by 12 hours. The POD NLPs had slightly less transfection activity but considerably lower cytotoxicity than the PEI‐DNA polyplex.

Conclusions

Of the PEG‐orthoester lipids tested, POD 2000 is the better choice for the preparation of sterically stabilized NLPs with a small particle diameter, good stability, low cytotoxicity, and satisfactory transfection activity. Copyright © 2004 John Wiley & Sons, Ltd.
Trend and variability of China precipitation in spring and summer: linkage to sea‐surface temperatures
Authors: Yang Fanglin , Lau K.‐M.
Published: November 2004

Observational records in the past 50 years show an upward trend of boreal‐summer precipitation over central eastern China and a downward trend over northern China. During boreal spring, the trend is upward over southeastern China and downward over central eastern China. This study explores the forcing mechanism of these trends in association with the global sea‐surface temperature (SST) variations on the interannual and interdecadal time scales.

Results based on singular value decomposition (SVD) analyses show that the interannual variability of China precipitation in boreal spring and summer can be well defined by two centres of action for each season, which are covarying with two interannual modes of SSTs. The first SVD modes of precipitation in spring and summer, which are centred in southeastern China and northern China respectively, are linked to an El Niño–southern oscillation (ENSO)‐like mode of SSTs. The second SVD modes of precipitation in both seasons are confined to central eastern China, and are primarily linked to SST variations over the warm pool and the Indian Ocean. Features of the anomalous 850 hPa winds and 700 hPa geopotential height corresponding to these modes support a physical mechanism that explains the causal links between the modal variations of precipitation and SSTs.

On the decadal and longer time scale, similar causal links are found between the same modes of precipitation and SSTs, except for the case of springtime precipitation over central eastern China. For this case, while the interannual mode of precipitation is positively correlated with the interannual variations of SSTs over the warm pool and Indian Ocean, the interdecadal mode is negatively correlated with a different SST mode, i.e. the North Pacific mode. The latter is responsible for the observed downward trend of springtime precipitation over central eastern China. For all other cases, both the interannual and interdecadal variations of precipitation can be explained by the same mode of SSTs. The upward trend of springtime precipitation over southeastern China and downward trend of summertime precipitation over northern China are attributable to the warming trend of the ENSO‐like mode. The recent frequent summertime floods over central eastern China are linked to the warming trend of SSTs over the warm pool and Indian Ocean. Copyright © 2004 Royal Meteorological Society
Spatial pattern in the precipitation regime of Nepal
Authors: Kansakar Sunil R. , Hannah David M. , Gerrard John , Rees Gwyn
Published: November 2004

A large‐scale perspective is provided upon the nature of precipitation regimes across Nepal by classifying long‐term mean monthly precipitation data for 222 stations. The classification methodology is shown to be a useful tool for identifying underlying spatial structure in precipitation regime shape (seasonal variability) and magnitude (size) in an extreme physical environment where climatological patterns are complex and poorly known. Four precipitation regime shape classes are identified: (a) July–August peaks are typical of western regions; (b) marked July peaks are characteristic of the central region and eastern lowlands; (c) July peaks with gradual onset are mainly concentrated in eastern Middle Mountains; and (d) July–August peaks with winter precipitation are confined to western higher mountains, particularly the Trans‐Himalayan region. Four precipitation regime magnitude classes are found: (a) low regimes clearly dominate western high‐mountain areas but occur more widely across the High Mountains and High Himalaya; (b) intermediate regimes are distributed from east to west at low altitude, dominating the western Terai/Siwaliks; (c) moderately high regimes are widespread but most evident in the Terai (plains) to Middle Mountains of central and eastern parts and eastern high mountains; and (d) high precipitation zones are situated near Pokhara and northeast of the Kathmandu Valley around Langtang. A composite (shape and magnitude) regime classification indicates the key controls upon spatial patterns in Nepalese precipitation to be: length and timing of the summer monsoon (duration decreases east to west with later onset and earlier withdrawal in the west); successively higher altitude, east–west‐trending mountain ranges causing rainfall to decline broadly south–north; topographic barriers that induce local rain shadows (lee) and precipitation hotspots (windward side); and westerly weather systems supplying winter precipitation to the northwest mountains. Although general patterns relating to zonal movement of the summer monsoon and physiographic (mountain ranges) controls upon precipitation may be identified, the role of mountainous relief in yielding localized precipitation patterns is significant. Copyright © 2004 Royal Meteorological Society
Anti‐apoptotic action of stem cell factor on oocytes in primordial follicles and its signal transduction
Authors: Jin Xuan , Han Chun‐Sheng , Yu Fu‐Qing , Wei Peng , Hu Zhao‐Yuan , Liu Yi‐Xun
Published: November 2004

Stem cell factor (SCF) is essential for the development of primordial follicles. One of its functions is to prevent oocytes from apoptosis. However, the underlying mechanism remains largely unknown. By using cultured ovaries that are rich in primordial follicles, the anti‐apoptotic action of SCF and the potential signal transduction pathways were investigated. The apoptosis was evaluated by means of in situ 3′‐end labeling. The expressions of proteins were analyzed with immunohistochemistry and Western blot. The data showed that SCF significantly prevented oocytes from apoptosis in the cultured organs. Addition of a specific pharmacological inhibitor of PI3K abolished the anti‐apoptotic action of SCF while that of a MEK inhibitor did not. The phosphorylation of two mitogen activated protein kinases (MAPKs) (p42 and p44) and AKT, the respective substrates of MEK and PI3K, were enhanced by SCF treatment. Not surprisingly, the MAPK activation occurred only in theca cells. The expressions of apoptosis‐related gene products, the Bcl‐2 family proteins, in response to SCF treatment were also investigated. While SCF up‐regulated the expression of the anti‐apoptotic proteins Bcl‐2 and Bcl‐xL, it did the opposite to the pro‐apoptotic factor Bax. The PI3K inhibitor reversed the regulation of SCF on Bcl‐xL and Bax but not on Bcl‐2. Therefore, it seemed that SCF initiated an anti‐apoptotic signal starting from its membrane receptor c‐kit to Bcl‐2 family members through PI3K/AKT and other signaling cascades in the oocytes of primordial follicles. Mol. Reprod. Dev. 70: 82–90, 2004. © 2004 Wiley‐Liss, Inc.
C‐kit receptor and its possible function in human spermatozoa
Authors: Feng Huai L. , Sandlow J.I. , Zheng L.J.
Published: November 2004

The presence and role of the c‐kit proto‐oncogene protein was investigated in the mature sperm of the human. A polyclonal antibody against the c‐kit peptide was used to perform immunohistochemical (IHC) staining, electron microscopy (EM) studies, and Western blot analysis. The acrosomal region of fresh sperm specifically stained with the antibody. No acrosomal staining or staining limited to the equatorial region was noted in the acrosome‐reacted (AR) sperm. EM studies demonstrated immunogold label on the plasma membrane (PM) of the acrosome, and confirmed the lack of binding following the acrosome reaction. A 150 kDa band was detected by Western blot analysis. This protein was released from the sperm surface during sperm capacitation and the acrosome reaction. Antibody against the c‐kit receptor significantly inhibited the acrosome reaction and increased sperm agglutination, but did not significantly inhibit sperm motility. These results suggest that the c‐kit receptor protein is present in mature human sperm and is released during capacitation and/or the acrosome reaction. The assessment of the c‐kit receptor may also be a useful assay for sperm function in male infertility. Mol. Reprod. Dev. 70: 103–110, 2004. © 2004 Wiley‐Liss, Inc.