bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel and sensitive test for rapid determination of water toxicity
Authors: Ulitzur S. , Lahav T. , Ulitzur N. 
Published: October 2002

AbstractThe performance of a novel, rapid, and sensitive test for detecting chemical toxicants in water is described in this article. The bioassay utilizes a highly sensitive variant of the luminescent bacterium Photobacterium leiognathi that allows the detection in water at levels below milligrams per liter of diverse groups of toxicants, including heavy metals, pesticides, PCBs, polycyclic aromatic hydrocarbons, and fuel traces. For most toxic agents reported in this study, the new assay was markedly more sensitive than the Microtox™ Vibrio fischeri assay according to the bacterial bioluminescence toxicity data reported in the literature. Additional features of the new bioassay include the ability to discriminate between cationic heavy metals and organic toxicants and the option of being run at ambient temperatures (18°C–27°C), thereby enabling on‐site testing with low‐cost luminometers. In addition, the stability of the freeze‐dried bacterial reagent preparation at ambient temperatures precludes the need for refrigeration or freezing during shipment, which contributes to further reducing overall operational costs. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 291–296, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10060
Effects of microcin SF608 and microcystin‐LR, two cyanotobacterial compounds produced by Microcystis sp., on aquatic organisms
Authors: Wiegand Claudia , Peuthert Anja , Pflugmacher Stephan , Carmeli Shmuel 
Published: October 2002

AbstractEffects of two cyanobacterial compounds, microcin SF608 and microcystin‐LR, were investigated on different physiological parameters of two organisms, the water moss, Vesicularia dubyana, and the waterflea, Daphnia magna. Both compounds are produced by Microcystis species. Microcystin‐LR is a potent inhibitor of protein phosphatases 1 and 2A, and microcin SF608 inhibits serine proteases. Other effects of microcystin‐LR are well documented in the literature, but adverse effects of microcin SF608 have not been investigated as yet. This study compared the effects of both compounds on detoxication enzymes, microsomal and soluble glutathione‐S‐transferase (m‐, sGST); oxygen stress enzymes, glutathione peroxidase (GP‐X), and peroxidase (POD); photosynthetic oxygen production and chlorophyll a:chlorophyll b ratio. mGST was inhibited by both compounds in both organisms, significantly by microcin SF608, possibly indirectly by inhibition of that serine protease transforming the mGST to its active form. The sGST of D. magna was inhibited by microcin SF608, but elevated by microcystin‐LR, and elevated by both compounds in V. dubyana. The GP‐X in D. magna was not altered by microcin SF608, but elevated parallel to the sGST, whereas the POD in V. dubyana was decreased by both. Photosynthetic oxygen production as well as the chlorophyll a/b ratio showed typical stress reactions, a decrease of oxygen production, and an increase of chlorophyll b, caused both by microcin SF608 and by microcystin‐LR. Microcin SF608 was not likely to be detoxified via conjugation to glutathione. The effects of microcin SF608 and microcystin‐LR demonstrate that the impact of cyanobacteria on other organisms may not only be directly related to the presently known toxins. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 400–406, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10065
Advanced techniques for interactive visualization of multi‐resolution meshes
Authors: Grabner Markus 
Published: October 2002

AbstractThis paper addresses the problem of interactive visualization of multi‐resolution triangle meshes. Visible switching between different levels of detail is avoided by smoothly interpolating mesh geometry between different levels. The interpolation parameter is derived from the screen‐space geometric error of the affected mesh region instead of assigning a fixed time to the transition. The shortcomings of straightforward frame rate control mechanisms (i.e., overshooting and oscillation) are avoided by a semi‐predictive algorithm. The average rendering time per triangle is measured and used to determine the desired number of faces. A set of experiments demonstrates the advantages of both methods. Copyright © 2002 John Wiley & Sons, Ltd.
High‐quality texture reconstruction from multiple views
Authors: Bornik Alexander , Karner Konrad , Bauer Joachim , Leberl Franz , Mayer Heinz 
Published: October 2002

AbstractThis paper presents a method to automatically calculate texture maps for a given three‐dimensional object out of a sequence of images. It is used in our image‐based modeling approach after the registration of the images and the geometric modeling is done. We show that the presented method uses the information from all images by implicitly applying a weighting function. Using this approach the consideration of modeled occlusions as well as the detection and removal of non‐modeled occlusions is accomplished. The final resolution of the texture maps can be adjusted on a pixel/cm basis. Copyright © 2002 John Wiley & Sons, Ltd.
State‐of‐the‐art in orthopaedic surgical navigation with a focus on medical image modalities
Authors: Langlotz Frank 
Published: October 2002

AbstractThis paper presents a review of surgical navigation systems in orthopaedics and categorizes these systems according to the image modalities that are used for the visualization of surgical action. Medical images used to be an essential part of surgical education and documentation as well as diagnosis and operation planning over many years. With the recent introduction of navigation techniques in orthopaedic surgery, a new field of application has been opened. Today surgical navigation systems — also known as image‐guided surgery systems — are available for various applications in orthopaedic surgery. They visualize the position and orientation of surgical instruments as graphical overlays onto a medical image of the operated anatomy on a computer monitor. Preoperative image data such as computed tomography scans or intraoperatively generated images (for example, ultrasonic, endoscopic or fluoroscopic images) are suitable for this purpose. A new category of medical images termed ‘surgeon‐defined anatomy’ has been developed that exclusively relies upon the usage of navigation technology. Points on the anatomy are digitized interactively by the surgeon and are used to build up an abstract geometrical model of the bony structures to be operated on. This technique may be used when no other image data is available or appropriate for a given application. Copyright © 2002 John Wiley & Sons, Ltd.
A study of profiled handoff for Diffserv‐based mobile nodes
Authors: Jaseemuddin Muhammad , Ahmed Zubairi Junaid , Mahmoud Omer 
Published: October 2002

AbstractThere is a growing interest in providing Internet services to the mobile nodes. When mobile nodes travel from one router's service area to another, the time‐sensitive applications may see degradation in service. We investigate into the effects of handoff on service quality of mobile nodes. Several experiments are conducted using various packet metering and marking schemes with or without transferring profiles to the new router. Results indicate the relative instability period following handoff, loss of packets and delay encountered by packets in profiled or un‐profiled handoffs, leading to determining suitable mix of metering and marking schemes with or without context transfer. Copyright © 2002 John Wiley & Sons, Ltd.
Challenges in modelling the unsteady aerodynamics of wind turbines
Authors: Leishman J. Gordon 
Published: October 2002

AbstractMany of the aerodynamic phenomena contributing to the observed effects on wind turbines are now known, but the details of the flow are still poorly understood and are challenging to predict accurately. This article emphasizes two key areas that need continued serious consideration for wind turbine predictive analyses: the modelling of the rotor wake and the modelling of the unsteady aerodynamics of the blade sections. Issues discussed herein include the modelling of the induced velocity field produced by the vortical wake behind the turbine, the various unsteady aerodynamic issues associated with the blade sections, and the non‐linear intricacies of dynamic stall. Fundamental limits exist in the capabilities of all models, and ambiguities can also arise in how these models should be properly applied. A challenge for analysts of the future is to use complementary experimental measurements and modelling techniques to better understand the aerodynamic problems found on wind turbines, and to develop more rigorous models with wider ranges of application. Copyright © 2002 John Wiley & Sons, Ltd.
Stop codon decoding in Candida albicans: from non‐standard back to standard
Authors: Moura Gabriela , Miranda Isabel , Cheesman Caroline , Tuite Mick F. , Santos Manuel A. S. 
Published: October 2002

AbstractThe human pathogen Candida albicans translates the standard leucine‐CUG codon as serine. This genetic code change is mediated by a novel ser‐tRNACAG, which induces aberrant mRNA decoding in vitro, resulting in retardation of the electrophoretic mobility of the polypeptides synthesized in its presence. These non‐standard decoding events have been attributed to readthrough of the UAG and UGA stop codons encoded by the Brome Mosaic Virus RNA 4, which codes for the virion coat protein, and the rabbit globin mRNAs, respectively. In order to fully elucidate the behaviour of the C. albicans ser‐tRNACAG towards stop codons, we have used other cell‐free translation systems and reporter genes. However, the reporter systems used encode several CUG codons, making it impossible to distinguish whether the slow migration of the polypeptides is caused by the replacement of leucines by serines at the CUG codons, readthrough, or a combination of both. Therefore, we have constructed new reporter systems lacking CUG codons and have used them to demonstrate that aberrant mRNA decoding in vitro is not a result from stop codon readthrough or any other non‐standard translational event. Our data show that a single leucine to serine replacement at only one of the four CUG codons encoded by the BMV RNA‐4 gene is responsible for the aberrant migration of the BMV coat protein on SDS–PAGE, suggesting that this amino acid substitution (ser for leu) significantly alters the structure of the virion coat protein. The data therefore show that the only aberrant event mediated by the ser‐tRNACAG is decoding of the leu‐CUG codon as serine. Copyright © 2002 John Wiley & Sons, Ltd.
A new insight into the suggestion of a possible antigenic role of a member of the 70 kD heat shock proteins.
Authors: Rocchi G. , Pavesi A. , Ferrari C. , Bolchi A. , Manara G. C. 
Published: October 2002

AbstractIn the present study the cellular distribution of the inducible (hsp72) and constitutive (hsc73) forms of human 70 kD heat shock protein was evaluated. A weak reactivity of the anti‐hsp72/hsc73 MoAb was found in the cytoplasm of the unstressed human epidermal cells, while stressed cells showed an enhanced reactivity at the cytoplasmic level and the expression of the molecules on the cell surface. Moreover, the antigenic properties of the two proteins were investigated by sequence analysis. Our findings provided evidence for at least three regions in the hsp72 which can be considered good candidates to represent T‐immunogenic antigens. This data as well as the cell surface localization of the hsp72 could suggest an antigenic role of the hsp72.
Phosphorylation pattern of liver proteins during the early stages of the acute‐phase response.
Authors: Piccoletti Roberta , Bendinelli Paola , Arienti Danilo , Maroni Paola , Bernelli‐Zazzera Aldo 
Published: October 2002

AbstractLiver preparations from turpentine‐treated rats show an increased capacity to autophosphorylate a protein of 32.5 kDa (p 32.5): both the kinase and the substrate protein are strongly bound to the membrane fraction, but the protein is released to the cytosol after phosphorylation, which occurs exclusively in serine residues. No known second messenger‐dependent protein kinase seems to be responsible for the reaction. Phosphorylation of p 32.5 could be an early post‐receptorial event after turpentine‐treatment possibly caused by cytokines and involved in the pathogenesis of further events of the acute‐phase response.
Differential sensitivity of human hepatoma cell line and primary rat hepatocyte culture to benzo(a)pyrene‐induced unscheduled DNA synthesis and adduct formation.
Authors: Liu Tsung‐Yun , Chao Tsurn‐Waan , Chiang Su‐Hua , Chi Chin‐Wen 
Published: October 2002

AbstractWe studied the genotoxic potential of a carcinogen in the human hepatoma cell line, HepG2 and in primary rat hepatocyte culture. HepG2 is a well differentiated human hepatoblastoma cell line with biotransforming capacity. Rat hepatocytes were obtained by the standard two‐step in situ perfusion technique. Following benzo(a)pyrene treatment, both HepG2 and primary rat hepatocyte culture showed unscheduled DNA synthesis with different sensitivity. In 32P‐postlabelling analysis, the chromatogram revealed quantitative and qualitative differences between HepG2 and primary rat hepatocyte cultures when treated with 10 μM benzo(a)pyrene for 18 hr. The results have demonstrated that the HepG2 cell line may be used in addition to primary rat hepatocytes in risk assessment for detection of environmental carcinogens.
Effect of silica on the spontaneous cytotoxicity of axial organ cells from Asterias rubens.
Authors: Leclerc M. , Bajelan M. , Barot R. , Tlaskalova‐Hogenova H. 
Published: October 2002

AbstractAxial organ cells (A.O.) which are composed of phagocytes and lymphocytes from the sea star Asterias rubens exert a spontaneous cytotoxicity against mouse tumour cells. This toxicity was tested in the presence or absence of silica. It appears that phagocytes play the role of killer cells.
Effect of extracellular matrix proteins on vascular smooth muscle cell phenotype
Authors: Hayward I. P. , Bridle K. R. , Campbell G. R. , Underwood P. A. , Campbell J. H. 
Published: October 2002

AbstractThe effect on phenotypic expression of rabbit vascular smooth muscle cells (SMC) of the interstitial matrix proteins collagen I and fibronectin, the basal lamina proteins collagen IV and laminin, and the serum adhesion protein vitronectin was examined in culture. Experiments were performed in foetal calf serum stripped of fibronectin and vitronectin to eliminate their confounding effects. All the proteins promoted adhesion to the plastic culture dish (in a concentration dependent manner) of SMC freshly isolated from the artery wall. These cells had a high volume density of myofilaments (Vvmyo) in their cytoplasm. Laminin was best at maintaining SMC with a high Vvmyo (Vvmyo = 49.8%) followed by collagen IV (41.7%). Cells plated on vitronectin showed the lowest Vvmyo (31.3%). The results support the concept that the SMC basal lamina has a role in maintaining cells in the high Vvmyo phenotype.
Maintenance of cytochrome P‐450 levels in hepatocytes preserved on gelatin gels
Authors: Evans Peter J. 
Published: October 2002

AbstractIn culture, cytochrome P‐450 levels fall rapidly with the result that hepatocytes are either used quickly or maintained in modified systems which prejudice their subsequent behaviour. In this study the effect of hypothermic preservation of hepatocytes on gelatin gels on levels of cytochrome P‐450 was investigated. In marked contrast to conventional cultures, hypothermic preservation (10°) maintained, over a 6‐day period, cytochrome P‐450 at levels similar to those of the more stable cytochrome b5. Cell storage on gelatin at 25° was associated with a conversion of cytochrome P‐450 to cytochrome P‐420. The procedure at 10° provides a valuable tool for toxicity testing, hepatocyte conservation and distribution.
Expression of α4 and β2 nicotinic acetylcholine receptor subunit mRNA and localization of α‐bungarotoxin binding proteins in the rat vestibular periphery
Authors: Wackym Phillip A. , Popper Paul , Lopez Ivan , Ishiyama Akira , Micevych Paul E. 
Published: October 2002

ABSTRACTIn situ hybridization histochemistry was used to map the distribution of α2, α3, α4, and β2 nAChR subunit mRNAs throughout the peripheral vestibular system of the rat. The α4 and β2 nAChR subunit genes were co‐expressed by populations of primary afferent neurons within Scarpa's ganglion, while there was no expression of the α2, α3, α4, or β2 nAChR subunit genes by type I or type II vestibular hair cells. α‐bungarotoxin binding to nAChRs in the vestibular end‐organs was primarily limited to the afferent chalices surrounding type I hair cells and the basal aspect of type II hair cells. These data suggest that nAChRs composed of α4 and β2 subunits are localized on afferent chalices innervating the type I vestibular hair cells and that the direct cholinergic efferent innervation of the type II vestibular hair cells utilizes nAChR composed of other subunits.
Transforming growth factor alpha.
Authors: Kumar V. , Bustin S. A. , McKay I. A. 
Published: October 2002

ABSTRACTTransforming growth factor alpha (TGFα) is a close relative of epidermal growth factor (EGF), the first polypeptide mitogen discovered in 1962 (Cohen, 1962). TGFα, like EGF, exerts its effect on cells through binding to the EGF‐Receptor (EGF‐R). Here we review the molecular and cell biology of TGFα before proceeding to describe our own work on signaling molecules induced in response to activation of the EGF‐R.
Platelet‐derived growth factor.
Authors: Meyer‐Ingold W. , Eichner W. 
Published: October 2002

ABSTRACTPlatelet‐derived growth factor (PDGF) is a potent activator for cells of mesenchymal origin. Two different PDGF chains termed A and B encoded by different genes have been identified leading to three different PDGF isoforms, the AA and BB homodimers and the AB heterodimer. All three forms have been observed in vivo and possess biological activity in vitro with the AA homodimer being the poorest cellular mitogen. The availability of highly purified recombinant PDGF isoforms was the initial basis for comparative studies in order to specify the different spectra of activity of the various PDGF species. This review is particularly focused on the AB heterodimer as from the standpoint of heterologous gene expression, this species is the one with the highest demands concerning expression and purification protocols. This explains the fact that, in comparison to PDGF‐BB, only very limited data on the in vivo application of PDGF‐AB are available so far.
Reconstituted human normal breast in nude mice using collagen gel or Matrigel.
Authors: Popnikolov Nikolay K. , Yang Jason , Guzman Raphael C. , Nandi Satyabrata 
Published: October 2002

AbstractHuman breast epithelial cells dissociated from reduction mammoplasty specimens were embedded in two commonly used extracellular matrices, type I collagen gel or Matrigel, and subsequently transplanted subcutaneously into athymic nude mice. Histological sections from both types of recovered gels showed epithelial structures arranged as short tubules with some branching as well as preservation of epithelial cell polarity. Proliferation was studied in vivo by 5‐bromo‐2′‐deoxy‐uridine labeling followed by immunostaining of sections from recovered gels. Human breast epithelia embedded in collagen gel or Matrigel had similar proliferative activity. Cholera toxin, 17β‐estradiol, and epidermal growth factor, when tested singly, were growth promoting, and in combination 17,β‐estradiol and cholera toxin had an additive effect but 17,β‐estradiol and epidermal growth factor were not additive. Our model system provides a means to study the endocrine control of normal human breast development.
Effects of bradykinin on Ca2+ mobilization and prostaglandin E2 release in human periodontal ligament cells.
Authors: Ogata Yorimasa , Niisato Naomi , Negishi Tetsuo , Sakurai Takeshi , Furuyama Shunsuke , Sugiya Hiroshi 
Published: October 2002

AbstractIn fura‐2‐loaded human periodontal ligament (HPDL) cells, bradykinin induced a rapidly transient increase and subsequently sustained increase in cytosolic Ca2+ ([Ca2+]i). When external Ca2+ was chelated by EGTA, the transient peak of [Ca2+]i was reduced and the sustained level was abolished, implying the Ca2+ mobilization consists of intracellular Ca2+ release and Ca2+ influx. Thapsigargin, a specific Ca2+‐ATPase inhibitor for inositol 1,4,5‐trisphosphate (1,4,5‐1P3)‐sensitive Ca2+ pool, induced an increase in [Ca2+]i in the absence of external Ca2+. After depletion of the intracellular Ca2+ pool by thapsigargin, the increase in [Ca2+]i induced by bradykinin was obviously reduced. Bradykinin also stimulated formation of inositol polyphosphates including 1,4,5‐IP3. These results suggest that bradykinin stimulates intracellular Ca2+ release from the 1,4,5‐1P3‐sensitive Ca2+ pool. Bradykinin stimulated prostaglandin E2 (PGE2) release in the presence of external Ca2+, but not in the absence of external Ca2+. Ca2+ ionophore A23187 and thapsigargin evoked the release of PGE2 in the presence of external Ca2+ despite no activation of bradykinin receptors. These results indicate that bradykinin induces Ca2+ mobilization via activation of phospholipase C and PGE2 release caused by the Ca2+ influx in HPDL cells.
Cell cycle‐dependent morphological changes in the actin cytoskeleton induced by agents which elevate cyclic AMP
Authors: McNamee Christine J. , Pennington Stephen R. , Sheterline Peter 
Published: October 2002

AbstractAgents which increase the intracellular concentration of cyclic adenosine‐5′‐monophosphate, induce a highly arborised morphology in a proportion of sub‐confluent Swiss 3T3 fibroblasts. During this process the organisation of actin filaments progessively changes from a characteristic stress fibre pattern to leave a network of actin filaments within each and every arborisation. Despite this massive reorganisation of the actin cytoskeleton no changes are observed in the extent of polymerisation of actin during arborisation. The proportion of cells in asynchronous cultures undergoing arborisation at maximal concentrations of agents reaches a maximum of 30%; suggesting that the effect might be mediated only in cells during a restricted period of the cell cycle. More than 80% of serum‐starved cells responded to these agents between 1 and 8 hours after readdition of serum, but not at other times, suggesting that the arborisation response can occur only in the G1 phase of the cell cycle.
PARTIAL CHARACTERIZATION OF A PUTATIVE 110kDa MYOSIN FROM THE GREEN ALGACHARA CORALLINABYIN VITROBINDING OF FLUORESCENT F‐ACTIN
Authors: GROLIG FRANZ , SCHRÖDER JAN , SAWITZKY HEIKO , LANGE ULF 
Published: October 2002

AbstractUsing the binding of heterologous, rhodamine phalloidin‐labelled F‐actinin vitro, two F‐actin binding proteins were identified in protein extracts from the green algaChara corallinaafter fractionation by anion exchange chromatography. The first protein, a putative myosin, released laterally bound F‐actin at ATP‐concentrations as low as 1μm; equivalent concentrations of ADP were not effective. Binding of F‐actin was inhibited by the sulfhydryl‐alkylating agent N‐ethylmaleimide (NEM). Binding of F‐actin was also abolished by a monoclonal anti‐myosin (J14) previously used for immunodetection and immunolocalization in internodal cells (Groliget al., 1988,Eur J Cell Biol47: 22–31). Immunoblotting with J14 detected a 110kDa polypeptide only in those protein fractions that had revealed ATP‐sensitive binding of F‐actin. The putative myosin bound with mediocre affinity to immobilized calmodulin and free Ca2+‐concentration made no difference to this binding affinity. In contrast to the putative myosin, the second, less abundant protein revealed ATP‐insensitive and end‐wise binding to the microfilament and was not recognized by the anti‐myosin antibody.