bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of channel width on alignment of smooth muscle cells by high‐aspect‐ratio microfabricated elastomeric cell culture scaffolds
Authors: Glawe John D. , Hill Jason B. , Mills David K. , McShane Michael J.
Published: July 2005

Engineered smooth muscle tissue requires ordered configurations of cells to reproduce native function, and microtechnology offers possibilities for physically and chemically controlling cell organization with high spatial resolution. In this work, poly(dimethylsiloxane) microchannel scaffolds, modified by layer‐by‐layer self‐assembly of polyelectrolytes to promote cell adhesion, were evaluated for use as substrates for the culture of aligned smooth muscle cells. The hypothesis that narrower channels would result in better alignment was tested using channel width dimensions of 20, 30, 40, 50, and 60 μm, in addition to flat (control) surfaces. Alignment of cells was assessed by two different methods, each sensitive to a different aspect of cell alignment from fluorescence micrographs. Two‐dimensional fast Fourier transform analysis was performed to analyze the orientation distribution of actin filaments in cells. This was complemented by connectivity analysis of stained nuclei to obtain nuclear orientation distributions. Both methods produced consistent data that support the hypothesis that narrow microchannels promote a highly aligned culture of smooth muscle cells, and the degree of alignment is dependent on the microchannel width. Precise replication of in vivo cell alignment in engineered tissue, with the ability to tailor specific surface chemistries of the scaffold to the desired application, will potentially allow the production of artificial tissue that more closely duplicates the structure and function of native tissue. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Midazolam suppresses thrombin‐induced heat shock protein 27 phosphorylation through inhibition of p38 mitogen‐activated protein kinase in cardiac myocytes
Authors: Tanabe Kumiko , Akamatsu Shigeru , Suga Hidetaka , Takai Shinji , Kato Kanefusa , Dohi Shuji , Kozawa Osamu
Published: July 2005

It has been shown that anesthetics have effects of cardiac preconditioning. Heat shock proteins (HSPs) function as molecular chaperone. Among them, HSP27, a low‐molecular‐weight HSP, abundantly exist in heart. However, the relationship between anesthetics and HSP27 in heart is not yet clarified. We investigated whether thrombin induces or phosphorylates HSP27 in primary cultured mouse myocytes and the effect of midazolam on the thrombin‐stimulated HSP27 phosphorylation and the mechanism behind it. Thrombin time dependently phosphorylated HSP27 at Ser‐15 and Ser‐85 while having no effect on the levels of HSP27. Midazolam markedly suppressed the thrombin‐induced phosphorylation of HSP27 at both Ser‐15 and Ser‐85. Thrombin induced the phosphorylation of p44/p42 MAP kinase and p38 MAP kinase without affecting stress‐activated protein kinase/c‐Jun N‐terminal kinase. In addition, midazolam attenuated the phosphorylation of thrombin‐induced p38 MAP kinase but not that of p44/p42 MAP kinase. SB203580 and PD169316, inhibitors of p38 MAP kinase, suppressed the thrombin‐induced phosphorylation of HSP27 at both Ser‐15 and Ser‐85. These results strongly suggest that thrombin induces the HSP27 phosphorylation at least through the p38 MAP kinase activation in cardiac myocytes and that midazolam inhibits the thrombin‐induced HSP27 phosphorylation via suppression of p38 MAP kinase activation. © 2005 Wiley‐Liss, Inc.
Mechanical loading stimulates ecto‐ATPase activity in human tendon cells
Authors: Tsuzaki M. , Bynum D. , Almekinders L. , Faber J. , Banes A.J.
Published: July 2005

Response to external stimuli such as mechanical signals is critical for normal function of cells, especially when subjected to repetitive motion. Tenocytes receive mechanical stimuli from the load‐bearing matrix as tension, compression, and shear stress during tendon gliding. Overloading a tendon by high strain, shear, or repetitive motion can cause matrix damage. Injury may induce cytokine expression, matrix metalloproteinase (MMP) expression and activation resulting in loss of biomechanical properties. These changes may result in tendinosis or tendinopathy. Alternatively, an immediate effector molecule may exist that acts in a signal‐dampening pathway. Adenosine 5′‐triphosphate (ATP) is a candidate signal blocker of mechanical stimuli. ATP suppresses load‐inducible inflammatory genes in human tendon cells in vitro. ATP and other extracellular nucleotide signaling are regulated efficiently by two distinct mechanisms: purinoceptors via specific receptor–ligand binding and ecto‐nucleotidases via the hydrolysis of specific nucleotide substrates. ATP is released from tendon cells by mechanical loading or by uridine 5′‐triphosphate (UTP) stimulation. We hypothesized that mechanical loading might stimulate ecto‐ATPase activity. Human tendon cells of surface epitenon (TSC) and internal compartment (TIF) were cyclically stretched (1 Hz, 0.035 strain, 2 h) with or without ATP. Aliquots of the supernatant fluids were collected at various time points, and ATP concentration (ATP) was determined by a luciferin‐luciferase bioluminescence assay. Total RNA was isolated from TSC and TIF (three patients) and mRNA expression for ecto‐nucleotidase was analyzed by RT‐PCR. Human tendon cells secreted ATP in vitro (0.5–1 nM). Exogenous ATP was hydrolyzed within minutes. Mechanical load stimulated ATPase activity. ATP was hydrolyzed in mechanically loaded cultures at a significantly greater rate compared to no load controls. Tenocytes (TSC and TIF) expressed ecto‐nucleotidase mRNA (ENTPD3 and ENPP1, ENPP2). These data suggest that motion may release ATP from tendon cells in vivo, where ecto‐ATPase may also be activated to hydrolyze ATP quickly. Ecto‐ATPase may act as a co‐modulator in ATP load‐signal modulation by regulating the half‐life of extracellular purine nucleotides. The extracellular ATP/ATPase system may be important for tendon homeostasis by protecting tendon cells from responding to excessive load signals and activating injurious pathways. © 2005 Wiley‐Liss, Inc.
Roles of Ca2+ and the Ca2+‐sensing receptor (CASR) in the expression of inducible NOS (nitric oxide synthase)‐2 and its BH4 (tetrahydrobiopterin)‐dependent activation in cytokine‐stimulated adult human astrocytes
Authors: Dal Pra Ilaria , Chiarini Anna , Nemeth Edward F. , Armato Ubaldo , Whitfield James F.
Published: July 2005

Since NO production by NOS‐2 made by astrocytes activated by proinflammatory cytokines contributes to the killing of neurons in variously damaged human brains, knowing the mechanisms responsible for NOS‐2 expression should contribute to developing effective therapeutics. The expression and activation of NOS‐2 in normal adult human cerebral cortical astrocytes treated with three proinflammatory cytokines, IL‐1β, TNF‐α, and IFN‐γ, are driven by two separable mechanisms. NOS‐2 expression requires a burst of p38 MAPK activity, while the activation of the resulting enzyme protein requires MEK/ERK‐dependent BH4 (tetrahydrobiopterin) synthesis between 24 and 24.5 h after adding the cytokines to the culture medium. Here we show that NOS‐2 expression in the activated astrocytes requires that the culture medium contain 1.8 mM Ca2+, but it is unaffected by inhibiting calcium‐sensing receptors (CASRs) with NPS 89636. However, NOS‐2 activation is inhibited by NPS 89626 during the MEK/ERK‐dependent stage between 24 and 24.5 h after adding the cytokines, and this inhibition can be overridden by exogenous BH4. Therefore, NOS‐2 expression and the subsequent BH4‐dependent NOS‐2‐activation in human astrocytes need 1.8 mM Ca2+ to be in the culture medium, while NOS‐2 activation also needs functional CASRs between 24 and 24.5 h after cytokine addition. These findings raise the possibility that calcilytic drugs prevent NO‐induced damage and death of human neurons. © 2005 Wiley‐Liss, Inc.
Dynamics of DNA repair suggested by the subcellular localization of Brca1 and Brca2 proteins
Authors: Huber L. Julie , Chodosh Lewis A.
Published: July 2005

The localization of proteins to specific subcellular compartments often reveals clues regarding their biological functions. Although significant progress has been made towards understanding how damaged DNA is repaired, experiments to date have primarily focused on signal transduction pathways that activate DNA repair protein complexes and on how these complexes are assembled. Current evidence suggests that certain DNA repair processes are spatially organized such that aberrant DNA structures can be brought into proximity with DNA repair proteins at fixed sites. Since biochemical evidence suggests that the tumor suppressor proteins, Brca1 and Brca2, may mediate the assembly of protein complexes involved in the repair of damaged DNA, we have performed subcellular fractionation experiments to determine the subnuclear localization of these proteins. The majority of Brca1 and Brca2 proteins were found to interact tightly with the nuclear matrix. Furthermore, within the limits of detection, localization of Brca1 and Brca2 to the nuclear matrix was not altered following treatment of cells with DNA damaging agents that activate homology‐mediated double‐stranded DNA break and transcription‐coupled repair pathways. Our findings suggest that Brca1 and Brca2 may perform their DNA repair‐related functions from positions that are anchored to the nuclear matrix. These data are consistent with proposed models that suggest that components of specific repair complexes residing on the nuclear matrix function to recruit damaged DNA. © 2005 Wiley‐Liss, Inc.
PAR1‐mediated NFκB activation promotes survival of prostate cancer cells through a Bcl‐xL‐dependent mechanism
Authors: Tantivejkul Kwanchanit , Loberg Robert D. , Mawocha Samkeliso C. , Day Lashon L. , John Lauren St. , Pienta Brian A. , Rubin Mark A. , Pienta Kenneth J.
Published: July 2005

We have previously reported that protease‐activated receptor 1 (PAR1 or thrombin receptor) is over‐expressed in metastatic prostate cancer cell lines compared to prostate epithelial cells. In this study, we examined 1,074 prostate biopsies by tissue microarray analysis and demonstrated that PAR1 expression is significantly increased in prostate cancer compared to normal prostate epithelial cells and benign prostatic hyperplasia. We hypothesized that PAR1 activation contributed to prostate cancer cell progression. We demonstrated that stimulation of PAR1 by thrombin or thrombin receptor activating peptide (TRAP6), in androgen‐independent DU145 and PC‐3 cells resulted in increased DNA binding activity of the NFκB p65 subunit. IL‐6 and IL‐8 levels were also elevated in conditioned media by at least two‐fold within 4–6 h of PAR1 activation. This induction of cytokine production was abrogated by pretreatment of cells with the NFκB inhibitor caffeic acid phorbol ester. The p38 and ERK1/2 MAPK signaling cascades were also activated by PAR1 stimulation, whereas the SAPK/JNK pathway was unaffected. Inhibition of p38 and ERK1/2 by SB‐203589 and PD‐098059, respectively, did not abrogate NFκB activity, suggesting an independent induction of NFκB by PAR1 stimulation. Furthermore, TUNEL assay showed that activation of PAR1 attenuated docetaxel induced apoptosis through the upregulation of the Bcl‐2 family protein Bcl‐xL. Akt activation was not observed, suggesting that drug resistance induced by PAR1 was independent of PI3K signaling pathway. Because thrombin and PAR1 are over‐expressed in prostate cancer patients, targeting the inhibition of their interaction may attenuate NFκB signaling transduction resulting in decreased drug resistance and subsequent survival of prostate cancer cells. © 2005 Wiley‐Liss, Inc.
Recombinant polyclonal antibodies for cancer therapy
Authors: Sharon Jacqueline , Liebman Meredith A. , Williams Brent R.
Published: July 2005

Although monoclonal antibodies are increasingly used for cancer therapy, remissions are only temporary due to emergence of tumor cell escape variants that are no longer affected by the antibody. The emergence of escape variants could be minimized by multi‐targeting of tumor cells with polyclonal antibodies, which would also be more efficient than monoclonal antibodies at mediating effector functions for target destruction. A technology for generating recombinant polyclonal antibodies for cancer therapy has been developed based on the construction and selection of tumor‐reactive Fab phage display libraries. The selected Fabs are mass‐converted to full‐length polyclonal antibody libraries (PCALs) of any isotype and any species. Prototypic PCALs generated against human colorectal cancer cell lines showed that libraries of diverse recombinant antibodies, enriched for reactivity to the cancer cells compared to normal human cells, can be obtained. The success of recombinant polyclonal antibodies as cancer therapeutics will depend on the ability to generate, characterize, and mass‐produce PCALs with high ratios of cancer‐to‐normal reactivities that cross‐react with many cancers of the same type. © 2005 Wiley‐Liss, Inc.
Garcinol modulates tyrosine phosphorylation of FAK and subsequently induces apoptosis through down‐regulation of Src, ERK, and Akt survival signaling in human colon cancer cells
Authors: Liao Chiung‐Ho , Sang Shengmin , Ho Chi‐Tang , Lin Jen‐Kun
Published: July 2005

Garcinol, from the fruit rind of Garcinia indica and other species, has been reported to suppress colonic aberrant crypt foci (ACF) formation in rats. In this study, we investigate the beneficial effects of tumor prevention by garcinol on the human colorectal cancer cell line, HT‐29. Focal adhesion kinase (FAK) is the major signaling mediator of integrin‐mediated cell–matrix contact‐regulated cellular proliferation, migration, and apoptosis in adherent cells. Results of Matrigel analysis show that exposure of HT‐29 cells to 10 µM garcinol inhibited cell invasion, and decreased the dose‐dependent tyrosine phosphorylation of FAK. We further demonstrate by Western blot analysis that garcinol inhibited activation of the Src, MAPK/ERK, and PI3K/Akt signaling pathways. To investigate whether the loss of integrin‐mediated cell–matrix contact can induce apoptosis, we demonstrate that garcinol induced it in HT‐29 cells. The apoptotic dose of garcinol (20 µM) changed the ratio of the anti‐apoptotic Bcl‐2 and proapoptotic BAX proteins within 12 h, which correlated with a release of cytochrome c from the mitochondria to the cytosol, and with PARP cleavage. Additionally, we demonstrate that a decreasing MMP‐7 protein level in HT‐29 cells results in sensitization to garcinol. Garcinol also significantly inhibited the expression of MMP‐7 in IL‐1β‐induced HT‐29 cells. These results suggest that garcinol reduces cell invasion and survival through the inhibition of FAK's downstream signaling. © 2005 Wiley‐Liss, Inc.
Iron–ascorbic acid‐induced oxidant stress and its quenching by paraoxonase 1 in HDL and the liver: Comparison between humans and rats
Authors: Trudel K. , Sinnett D. , James R.W. , Delvin E. , Amre D. , Seidman E. , Levy E.
Published: July 2005

Paraoxonase 1 (PON1) is a serum enzyme closely associated with high‐density lipoprotein (HDL), which may protect against atherosclerosis by hydrolyzing lipid peroxides and several organophosphorus compounds. The purpose of the present study was to test the hypothesis that lipid peroxidation modifies the activity and protein mass of PON1 in humans and rats. Our findings revealed that the bulk of the activity monitored by the hydrolysis of paraoxon and phenyl acetate was confined to liver intracellular endoplasmic reticulum‐derived microsomes and was mostly recovered in circulating HDL3. Confirmation was obtained by the determination of PON1 expression by Western blot. It is noteworthy that PON1 levels were consistently decreased in human sera, HDL, and liver microsomes compared with rat counterparts. Concomitant with iron‐ascorbate‐mediated lipid peroxidation, there was a decline in PON1 activity and protein in both HDL3 and microsomes, which was attenuated by butylated hydroxytoluene antioxidant treatment. The current data indicate that PON1 localization in microsomes and HDL3 could represent a selective cellular and lipoprotein response to oxidative stress. This was tested by the iron‐ascorbate oxygen‐radical generating system. It is also proposed that the increased PON1 level may have a function related to the well‐known atherosclerosis resistance of rats. © 2005 Wiley‐Liss, Inc.
Salvianolic acid B attenuates plasminogen activator inhibitor type 1 production in TNF‐α treated human umbilical vein endothelial cells
Authors: Zhou Zhe , Liu Yong , Miao Ai‐Dong , Wang Sheng‐Qi
Published: July 2005

Plasminogen activator inhibitor type 1 (PAI‐1), which plays a role in the development of atherosclerosis, is produced by endothelial cells following stimulation with various inflammatory cytokines such as tumor necrosis factor (TNF‐α). In the present study, we investigated the effects of a potent water‐soluble antioxidant, salvianolic acid B (SalB; derived from the Chinese herb, Salvia miltiorrhiza), on the expression of PAI‐1 in TNF‐α‐treated human umbilical vein endothelial cells (HUVECs). We found that SalB inhibited TNF‐α‐induced PAI‐1 mRNA production and protein secretion in HUVECs. Treatment with SalB (0.05 and 0.15 µM) notably attenuated TNF‐α induced expression of PAI‐1 to 90.5% and 74.6%, respectively, after 12 h, and to 75.1% and 64.2%, respectively, after 18 h. We also observed a dose‐dependent decrease in PAI‐1 protein production in the presence of SalB. We then used pathway inhibitors to investigate which step of the TNF‐α induced signaling pathway was targeted by SalB. We found that the c‐Jun N‐terminal kinase (JNK) inhibitor, SP600125, increased the inhibitory effects of SalB on TNF‐α‐induced PAI‐1 secretion, whereas the nuclear factor‐κB (NF‐κB) inhibitor, emodin, and the extracellular signal‐regulated kinase (ERK) inhibitor, PD98059, did not. A gel shift assay further showed that SalB inhibited the TNF‐α‐activated NF‐κB and AP‐1 DNA binding activities in a dose‐dependent manner. Collectively, these results indicate that the NF‐κB and ERK‐AP‐1 pathways are possible targets of SalB in the regulation of TNF‐α‐stimulated PAI‐1 production in HUVECs. © 2005 Wiley‐Liss, Inc.
Sp1 and Sp3 regulate the basal transcription of receptor activator of nuclear factor kappa B ligand gene in osteoblasts and bone marrow stromal cells
Authors: Liu Jianzhong , Yang Hongmei , Liu Wei , Cao Xuemei , Feng Xu
Published: July 2005

Receptor activator of nuclear factor kappa B ligand (RANKL), a potent regulator of osteoclast formation and function, is expressed by osteoblasts and bone marrow stromal cells. However, the molecular mechanism underlying RANKL expression in osteoblast/stromal cells remains largely unclear. Here, we characterized the molecular mechanism controlling RANKL basal transcription in osteoblast/stromal cells. We cloned a 1,103‐bp murine RANKL promoter (from −953 to +150, relative to the transcription start site). Using a series of deletion mutants of the 1,103‐bp promoter, we identified a 100‐bp region (−154 to −54) mediating RANKL basal transcription in both osteoblasts and bone marrow stromal cells. Electrophoretic mobility shift assay (EMSA) using five overlapping oligonucleotides (Probes 1–5) spanning the 100‐bp region showed that Probes 1 and 2 specifically bound nuclear proteins with high affinity from both cell types. Computer analysis revealed that Probes 1 and 2 contain a putative Sp1‐binding site. Supershift assays with Sp1 and Sp3 antibodies confirmed that the nuclear proteins binding to Probes 1 and 2 are Sp1 and Sp3. Functionally, the mutation of the Sp1/Sp3 site in Probe 1 profoundly reduced the basal promoter activity while the mutation of the one in Probe 2 resulted in moderate reduction in the basal promoter activity. Moreover, the mutation of both sites abrogated the RANKL basal promoter activity, indicating that Sp1 and Sp3 play a key role in the RANKL basal transcription in osteoblasts and bone marrow stromal cells. © 2005 Wiley‐Liss, Inc.
PARP‐1‐dependent 3‐nitrotyrosine protein modification after DNA damage
Authors: Siles E. , Martinez‐Lara E. , Núñez M.I. , Muñoz‐Gámez J.A. , Martín‐Oliva D. , Valenzuela M.T. , Peinado M.A. , Ruiz de Almodóvar J.M. , Javier Oliver F.
Published: July 2005

3‐nitrotyrosine (NO2‐Tyr) is thought to be a specific marker of cell injury during oxidative damage. We have evaluated the role of poly(ADP‐ribose)polymerase‐1 (PARP‐1) in protein nitration after treatment of immortalized fibroblasts parp‐1+/+ and parp‐1−/− with the alkylating agent 2′‐methyl‐2′‐nitroso‐urea (MNU). Both cell lines showed increased iNOS expression following MNU treatment in parallel with a selective induction of tyrosine nitration of different proteins. PARP‐1 deficient cells displayed a delayed iNOS accumulation, reduced number of nitrated proteins, and a lower global nitrotyrosine “footprint.” We have identified the mitochondrial compartment as the major site of oxidative stress during DNA damage, being MnSOD one of the NO2‐Tyr‐modified proteins, but not in parp‐1−/− cells. These results suggest that NO‐derived injury can be modulated by proteins involved in the response to genotoxic damage, such as PARP‐1, and may account for the limited oxidative injury in parp‐1 knockout mice during carcinogenesis and inflammation. © 2005 Wiley‐Liss, Inc.
Accurate mass measurement for the determination of elemental formula—A tutorial
Authors: Bristow Anthony W.T.
Published: July 2005

The application of accurate mass measurement for the determination of elemental formula has its origin in the 1950s and for many years was only carried out using magnetic sector mass spectrometers. The availability of such measurements was limited due to the cost and complexity of the instrumentation and the need for considerable expertise to acquire and interpret the spectra. In recent years the incredible pace of instrumental development has changed this, particularly with the renaissance of time of flight mass spectrometry. This has resulted in instrumentation capable of making accurate mass measurements in a robust fashion becoming available to most practitioners of (mass spectrometry) MS, without some of the earlier technical challenges and at lower cost. In this review the variety of accurate mass measurement instrumentation and techniques and their relative capabilities are discussed, along with a range of applications requiring the determination of elemental formula. © 2005 Wiley Periodicals, Inc.
A comparison of capillary‐scale LC–NMR with alternative techniques: spectroscopic and practical considerations
Authors: Lewis Richard J. , Bernstein Michael A. , Duncan Sara J. , Sleigh Chris J.
Published: July 2005

Experimental and practical details for the use of capillary LC (CapLC)–NMR are reported. The capillary NMR probe has high sensitivity and excellent flow characteristics and we found CapLC–NMR to be best suited to samples that are truly mass limited. CapLC–NMR relies on good capillary‐scale chromatography where highly concentrated peaks with a volume closely matched to the NMR flow cell are achievable. Provided that the loading capacity of the capillary column is not limiting, the combination of high sensitivity and high solvent suppression quality makes CapLC–NMR an excellent choice. For many real samples, however, the loading is limiting and we found the combination of LC–SPE–MS–NMR with a cryoprobe enables more material to be purified for NMR analysis, while retaining sensitivity. Copyright © 2005 John Wiley & Sons, Ltd.
Nuclear magnetic resonance coupled microseparations
Authors: Webb A. G.
Published: July 2005

The increased separation efficiency afforded by reducing the size of the separation column has resulted in ‘microseparations’ becoming an important component in many chemical and biochemical applications. The coupling of microseparations with NMR detection is an area of increasing interest owing to the high structural information of NMR. In order to couple efficiently with the separation, the NMR detector must be reduced in size to correspond to that of the separation peak. This paper summarizes some of the approaches used in coupling NMR detection with pressure‐driven and electrophoretic microseparations, the design of small NMR detectors and applications of this technology. Copyright © 2005 John Wiley & Sons, Ltd.
The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis
Authors: Xu Feng , Alexander Anthony J.
Published: July 2005

This paper reports the design of an on‐line semi‐preparative LC–SPE–NMR system and its use in the structural analysis of mixture components at the 0.02–1% level. The combination provides at least a five fold mass sensitivity increase over that obtained from typical analytical LC–SPE systems and a >30‐fold total NMR sensitivity enhancement over analysis by LC–NMR. This is accomplished by using a novel on‐line device to store, dilute (1–100‐fold) and deliver (at an optimized flow‐rate) the isolated component of interest to an SPE trap unit. The SPE unit consists of two cartridges connected in parallel to increase the overall SPE capacity and also to decrease the flow‐rate through each trap for enhanced trapping efficiency. As the coupling of semi‐preparative LC with NMR (through SPE) is well matched in terms of optimal mass loading for both techniques, only one LC–SPE cycle is required to enrich a 50 µg ml−1 component (1% in a 5 mg ml−1 mixture) for the acquisition of heteronuclear 1H–13C NMR data using a conventional NMR flow probe. Furthermore, analytes at the 0.02% level (∼1 µg ml−1) can be studied using 2D 1H NMR techniques if peak cuts from replicate sample injections (≥3) are accumulated into the storage/dilution unit and the resulting solution processed by just one SPE trap and elute cycle. Copyright © 2005 John Wiley & Sons, Ltd.
LC–NMR coupling technology: recent advancements and applications in natural products analysis
Authors: Exarchou Vassiliki , Krucker Manfred , van Beek Teris A. , Vervoort Jacques , Gerothanassis Ioannis P. , Albert Klaus
Published: July 2005

An overview of recent advances in nuclear magnetic resonance (NMR) coupled with separation technologies and their application in natural product analysis is given and discussed. The different modes of LC–NMR operation are described, as well as how technical improvements assist in establishing LC–NMR as an important tool in the analysis of plant‐derived compounds. On‐flow, stopped‐flow and loop‐storage procedures are mentioned, together with the new LC–SPE–NMR configuration. The implementation of mass spectrometry in LC–NMR is also useful on account of the molecular weight and fragmentation information that it provides, especially when new plant species are studied. Cryogenic technology and capillary LC–NMR are the other important recent developments. Since the plant kingdom is endless in producing potential drug candidates, development and optimization of LC–NMR techniques convert the study of natural products to a less‐time‐consuming task, speeding up identification. Copyright © 2005 John Wiley & Sons, Ltd.
Smad3 signalling plays an important role in keloid pathogenesis via epithelial–mesenchymal interactions
Authors: Phan TT , Lim IJ , Aalami O , Lorget F , Khoo A , Tan EK , Mukhopadhyay A , Longaker MT
Published: July 2005

Smad signalling plays important roles in developmental and cancer biology as well as in fibropathogenesis. Its role in keloid biology is not known. Epithelial–mesenchymal interactions, originally described in normal skin, have recently been established to play a significant role in keloid pathogenesis, and demonstrate the important influence of keratinocyte paracrine factor signalling on fibroblast behaviour. The present study investigated the role of downstream Smad cascade induction in this interaction. Normal fibroblasts (NF) and keloid fibroblasts (KF) were co‐cultured in serum‐free medium with normal keratinocytes (NK) or keloid keratinocytes (KK) for 5 days, after which fibroblast cell lysates were subjected to western blot and immunoprecipitation analysis to quantify the levels of Smad and Smad2/3/4 binding complex. In another set of experiments, wild‐type (wt), Smad2‐null (Smad2−/−) and Smad3‐null (Smad3−/−) mouse embryonic fibroblasts (MEF) were assayed for cell proliferation and collagen production after serum‐free co‐culture with KK or exposure to conditioned media collected from serum‐free KK/KF co‐culture. Compared to normal skin, keloids expressed high basal levels of TGFβR1 and TGFβR2, Smad2, 3 and 4 and phospho‐Smad2. Upregulation of TGFβR1 and TGFβR2, Smad3 and p‐Smad2 was observed in KF co‐cultured with KK, together with enhanced Smad3 phosphorylation and Smad2/3/4 binding complex production. When MEF‐wt, MEF‐Smad2−/− or MEF‐Smad3−/− were co‐cultured with KK or exposed to KK/KF co‐culture conditioned media, enhanced proliferation and collagen production were seen in MEF‐wt and MEF‐Smad2−/− but not in MEF‐Smad3−/− cells. The activation of Smad signalling, importantly that of Smad3, appears to be one facet of the complex epithelial–mesenchymal interactions in keloid pathogenesis, resulting in active KF proliferation and collagen‐ECM production in co‐culture with KK. This finding suggests the suppression of Smad signalling as a novel approach in keloid therapy. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Evaluation of piezoelectric PVDF polymers for use in space environments. II. Effects of atomic oxygen and vacuum UV exposure
Authors: Dargaville Tim R. , Celina Mathew , Martin Jeffrey W. , Banks Bruce A.
Published: July 2005

The effects of atomic oxygen (AO) and vacuum UV radiation simulating low Earth orbit conditions on two commercially available piezoelectric polymer films, poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene) P(VDF‐TrFE), have been studied. Surface erosion and pattern development are significant for both polymers. Erosion yields were determined as 2.8 × 10−24 cm3/atom for PVDF and 2.5 × 10−24 cm3/atom for P(VDF‐TrFE). The piezoelectric properties of the residual material of both polymers were largely unchanged after exposure, although a slight shift in the Curie transition of the P(VDF‐TrFE) was observed. A lightly cross‐linked network was formed in the copolymer presumably because of penetrating vacuum ultraviolet (VUV) radiation, while the homopolymer remained uncross‐linked. These differences were attributed to varying degrees of crystallinity and potentially greater absorption, and hence damage, of VUV radiation in P(VDF‐TrFE) compared with PVDF. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2503–2513, 2005
Immer auf Kurs – Wertorientierte Unternehmensführung: Risikomanagement, Strategie und Controlling verbinden
Authors: Gleißner Werner
Published: July 2005

Wertorientiertes Management zeichnet sich durch seine Orientierung am langfristigen Erfolg und die Berücksichtigung von Risiken durch die Unvorhersehbarkeit der Zukunft aus. Ein so verstandenes wertorientiertes Management findet man häufig auch bei mittelständischen Unternehmen – allerdings ohne, dass diese ihre Unternehmensführung zwingend mit “wertorientiert” beschreiben würden. Unternehmensziele, wie ein “nachhaltiges profitables Wachstum” sind jedoch eng mit dem Unternehmenswert verwandt.
A DFIG wind turbine ride‐through system. Influence on the energy production
Authors: Petersson A. , Lundberg S. , Thiringer T.
Published: July 2005

The influence of a voltage sag ride‐through system on the energy production of a doubly‐fed induction generator (DFIG) wind turbine is investigated. Using simulations, a candidate ride‐through system based on insulated gate bipolar transistor (IGBT) modules with high current rating and with the option of having antiparallel thyristors, which can quickly disconnect the stator of the DFIG from the grid, is developed. It has been found that, by increasing the current rating of the converter IGBTs, the losses of the converter can be reduced. However, if antiparallel thyristors have to be connected between the stator and the grid in order to achieve a fast disconnection of the stator circuit, the overall losses of the total system increase instead. Copyright © 2005 John Wiley & Sons, Ltd.
Grid interaction of offshore wind farms. Part 1. Models for dynamic simulation
Authors: Morren Johan , Pierik Jan T. G. , Haan Sjoerd W. H. de , Bozelie Jan
Published: July 2005

In this contribution, dynamic wind farm models suitable for fast simulation of power systems are presented. While deriving the models, special attention has been paid to increasing the computational speed of the simulation program. An important increase in speed is realized by the use of the well‐known dq0 transformation (Park transformation) not only for the generator but also for all other electrical components. The use of the Park transformation is common practice in electrical machine models, but not in the modelling of other electrical components. For single turbines, simulations in the dq0 reference frame are 100 times faster than simulations in the abc reference frame. After a discussion of the Park transformation and its most important properties, it is explained how models in the dq0 reference frame can be obtained. The dq0 models of the most important electrical components are presented. The mechanical and aerodynamic models that are needed for dynamic simulation of wind turbines are discussed briefly. The models are applied in Part 2. Copyright © 2005 John Wiley & Sons, Ltd.
International comparison of requirements for connection of wind turbines to power systems
Authors: Jauch Clemens , Matevosyan Julija , Ackermann Thomas , Bolik Sigrid
Published: July 2005

Power production from wind turbines has increased considerably during the last decade. Therefore today's wind turbines, which are typically set up in wind farms, have a significant influence on the operation of power systems. The efficient and secure operation of power systems is supported by grid codes, which are sets of requirements for all network users (suppliers, customers, etc.). In Europe, several transmission network operators have introduced special grid connection requirements for wind farms. These requirements are mainly based on existing grid codes, initially written for conventional power plants usually equipped with synchronous generators. This article presents a comparison of grid connection requirements for wind farms issued, or proposed as a draft, by transmission network operators in Denmark, Sweden, Germany, Scotland and Ireland. Copyright © 2005 John Wiley & Sons, Ltd.
Design of robust converter interface for wind power applications
Authors: Magueed Fainan A. , Sannino Ambra , Svensson Jan
Published: July 2005

As the amount of wind power and other distributed generation with power electronic interface in the grid grows, it becomes unacceptable to disconnect generating units every time a disturbance occurs, as was common practice in the past. Keeping the voltage source converter on‐line during unbalanced voltage dips thus becomes a very critical issue. In this article the design of a robust converter interface for wind turbines is investigated. Based on the classification of unbalanced faults that can occur in the grid, resulting in voltage dips at the bus where the turbine is connected, the maximum current that the converter valves must be able to withstand is calculated. The effect of phase angle jumps during faults is also investigated. It is demonstrated that, ultimately, the converter design can be optimized by using statistics of voltage dips and the wind speed distribution for the specific site considered. This is shown by a design example. Copyright © 2005 John Wiley & Sons, Ltd.
Field tests and modelling of a wind farm with doubly fed induction generators
Authors: Meisingset Magne , Ohnstad Trond M. , Uhlen Kjetil , Strand Leif R.
Published: July 2005

Havøygavlen is Norway's second wind farm and started operation in 2002. Several new wind farms are currently under planning at various sites along the Norwegian coast. The Norwegian transmission system operator (TSO) Statnett SF and Sintef Energy Research have jointly developed a dynamic simulation model for Havøygavlen in order to analyse the interaction between wind farms and the transmission grid. Full‐scale field tests have been conducted to investigate the dynamic behaviour of the wind farm and to verify the model by comparing simulations with measurements. This article presents results from the field tests, model validation work as well as operating experiences for Havøygavlen wind farm. Copyright © 2005 John Wiley & Sons, Ltd.
Impact of selective predation by Mesocyclops pehpeiensis on a zooplankton community: experimental analysis using mesocosms
Authors: Chang Kwang‐Hyeon , Hanazato Takayuki
Published: July 2005

Predation by cyclopoid copepods is an important factor affecting zooplankton communities in freshwater habitats. Experiments provide strong evidence of the role of selective predation by cyclopoid copepods in structuring zooplankton communities. To assess the predation impact of a cyclopoid copepod, Mesocyclopspehpeiensis, we conducted a mesocosm experiment using 20‐l polyethylene tanks in which the density of the predator and the food available to herbivorous zooplankton varied. M. pehpeiensis had a notable but selective effect on the zooplankton community. The population of a small cladoceran, Bosmina fatalis was affected negatively, but M. pehpeiensis did not have any apparent impact on the population dynamics of another Bosmina species, B. longirostris. On the other hand, the population of small rotifers responded positively to the presence of M. pehpeiensis, and their densities increased in mesocosms with a high density of M. pehpeiensis. It seems that suppression of B. fatalis by M. pehpeiensis predation indirectly affected rotifers by releasing them from competition with B. fatalis. The results suggest that copepod predation is a powerful factor regulating zooplankton communities directly and indirectly.
Diabetes mellitus and cardiogenic shock in acute myocardial infarction
Authors: Lindholm M.G. , Boesgaard S. , Torp‐Pedersen C. , Køber L. ,   on behalf of the TRACE registry study group
Published: July 2005

Aims

Cardiogenic shock is the leading cause of in‐hospital mortality after acute myocardial infarction (MI). This study investigates the importance of age and preexisting diabetes mellitus on the incidence and prognosis of cardiogenic shock in a large group of consecutive patients with MI.

Methods and results

Baseline characteristics and in‐hospital complications to the infarction were prospectively recorded in 6676 patients with MI. Ten‐year mortality was collected. Diabetes was present in 10.8% of the total population. A total of 443 developed cardiogenic shock with an incidence of 6.2% among nondiabetics and 10.6% among diabetics. Age, wall motion index, reinfarction, and the absence of thrombolytic treatment were significant independent predictors of mortality in patients with cardiogenic shock. Intriguingly, diabetes was not a significant predictor for short‐ and long‐term mortality in this population. The 30‐day and 5‐year mortality rate was equally poor in both diabetic and nondiabetic patients with cardiogenic shock (diabetics: 30‐day 63%, 5‐year 91%; nondiabetics: 30‐day 62%, 5‐year 86%; p>0.05).

Conclusions

Cardiogenic shock develops approximately twice as often among diabetics as among nondiabetic patients with acute MI. The prognosis of diabetics with cardiogenic shock is similar to the prognosis of nondiabetic patients with cardiogenic shock.
Prevalence and predictors of anxiety and depression in a sample of chronic heart failure patients with left ventricular systolic dysfunction
Authors: Haworth J.E. , Moniz‐Cook E. , Clark A.L. , Wang M. , Waddington R. , Cleland J.G.F.
Published: July 2005

Objective

To determine the prevalence and predictors of anxiety and depression in patients with heart failure due to Left Ventricular Systolic Dysfunction (LVSD).

Background

Psychological adjustment to Chronic Heart Failure (CHF) can be poor, with the prevalence of depression in out‐patients ranging from 13% to 48%. The prevalence of anxiety disorders in this population is unknown and the factors that predict anxiety and depression are not well understood.

Methods

100 out‐patients from a community heart failure programme completed a clinical diagnostic interview—the Structured Clinical Interview (SCID‐I), to evaluate anxiety and depression. Mean age was 67 ± 11 years, 17% were women and 91% were NYHA Class II or III. Other standardised measures were of cognition, biomedical status, social support and previous physical and mental health history.

Results

The prevalence rates of anxiety and depression (all subtypes) were 18.4% and 28.6%, respectively. Predictors of depression included a reported history of mental ill‐health and NYHA class. Predictors of anxiety included a reported history of mental ill‐health, co‐morbid physical illness (diabetes and angina) and NYHA class. Severity of LVSD did not predict either anxiety or depression.

Conclusions

Both anxiety and depression are common in CHF patients. The data on the predictors of poor psychological adjustment might assist in targeting bio‐psychosocial intervention for patients who are at most at risk of anxiety and depression, within community CHF disease management programmes.
Short to long term mortality of patients hospitalised with heart failure in the Czech Republic—a report from the EuroHeart Failure Survey
Authors: Rosolova Hana , Cech Jakub , Simon Jaroslav , Spinar Jindrich , Jandova Ruzena , Widimský sen Jiri , Holubec Lubomir , Topolcan Ondrej
Published: July 2005

Background and aim:

The European Society of Cardiology initiated the EuroHeart Failure Survey to obtain more data about the quality of care in patients hospitalised with suspected heart failure (HF). The Czech Republic was 1 of the 24 European Society countries included in the survey. The aim of this report is to extend the original follow‐up period of 12 weeks out to 4 years to assess mortality.

Methods:

All admitted patients were screened according to the EuroHeart Survey Protocol, over a 6‐week period in six hospitals in Pilsen, Prague and Brno in the year 2000. Annual mortality and cause of death were obtained from the Prague Institute for Health Statistical Information (UZIS Praha).

Results:

A total of 2365 patients were screened and about 25% of all admitted patients fulfilled the criteria for HF. About 14% of patients died between admission and the 12‐week follow‐up, 36% of male and 42% of female patients died during the 4‐year follow‐up (2000–2003). Cardiovascular diseases were the main causes of death (92%). Deceased patients were significantly older, had lower haemoglobin and total plasma cholesterol level, and had renal insufficiency and higher levels of big endothelin and BNP than the survivors. Mortality risk was increased independently by positive history of previous myocardial infarction OR=2.39 (1.59–3.59), by age OR=1.03 (1.01–1.05) and by plasma creatinine level OR=1.04 (1.01–1.07). Treatment with diuretics and digoxin was associated with a higher risk of death; by contrast, a protective effect of beta‐blockers and statins was found in these HF patients.

Conclusion:

Patients with HF were older and had a poor prognosis; approximately one third of the patients will die within 3 years.
Short‐ and long‐term results of a programme for the prevention of readmissions and mortality in patients with heart failure: Are effects maintained after stopping the programme?
Authors: Ojeda Soledad , Anguita Manuel , Delgado Mónica , Atienza Felipe , Rus Carmen , Granados Amador L. , Ridocci Federico , Vallés Federico , Velasco Jose A.
Published: July 2005

The objective of the study was to evaluate whether improvements obtained during an intervention programme were maintained after the programme was stopped. 153 patients discharged with a diagnosis of heart failure (HF) were randomized to either usual care or an intervention programme, which included patient education, consultation with the cardiologist and monitoring in the Heart Failure Unit. After an average period of 16±8 months, the intervention programme was stopped. One year later, all the patients were re‐examined to assess HF readmissions, all‐cause mortality, quality of life, and prescribed medical treatment. During the 16±8‐month treatment period, patients in the intervention group had a lower rate of HF readmissions (17% vs. 51%, p<0.01), less all‐cause mortality (13% vs. 27%, p=0.03), improvement in quality of life (1.5±0.8 vs. 1.9±1, p=0.03) and optimisation of medical treatment was achieved. One year after stopping the intervention, there was no difference in HF readmissions (28% vs. 25%, p=0.72), all‐cause mortality (14% vs. 17%, p=0.64) and quality of life (1.7±0.9 vs. 1.8±1, p=0.24) between the groups. Survival and the probability of not being readmitted due to HF were similar in both groups. There was also a reduction in the use of beta‐blockers and spironolactone in the intervention group.

Conclusions

The positive effects of an intervention programme are clearly reduced when it is stopped, due to less strict control of the patients and a decrease in the use of drugs with proven efficacy in HF.
Tendon xanthomas in familial hypercholesterolemia are associated with a differential inflammatory response of macrophages to oxidized LDL
Authors: Artieda Marta , Cenarro Ana , Junquera Corina , Lasierra Pilar , Martínez-Lorenzo María José , Pocoví Miguel , Civeira Fernando
Published: July 2005

Tendon xanthomas (TX) are pathognomonic lipid deposits commonly found in familial hypercholesterolemia (FH) patients. The aim of this study was to determine whether macrophages from FH patients with TX (TX+) have higher predisposition to foam cells formation after oxidized LDL (oxLDL) overload than those from FH patients without TX (TX−), and if their differential gene expression profile could explain these different phenotypes. Total RNA pools from macrophages from FH patients TX+ and TX− were analyzed using Affymetrix oligonucleotide arrays to evaluate the gene expression profile in presence and absence of oxLDL. Also, the intracellular lipid content was measured by fluorescence flow cytometry. Results of these studies suggest that macrophages from FH subjects TX+ compared to those TX− have a differential response to oxLDL, since they show higher intracellular cholesterol ester accumulation and a differential gene expression profile. The gene array data were validated by relative quantitative real‐time RT‐PCR and quantitative ELISA in culture media and plasma samples. FH subjects TX+ showed increased plasma tryptase, TNF‐α, IL‐8 and IL‐6 concentrations. We propose that TX formation are associated with higher intracellular lipid content, and higher inflammatory response of macrophages in response to oxLDL.
Oxygenated complex of cytochrome bd from Escherichia coli: Stability and photolability
Authors: Belevich Ilya , Borisov Vitaliy B. , Konstantinov Alexander A. , Verkhovsky Michael I.
Published: July 2005

Cytochrome bd is one of the two terminal ubiquinol oxidases in the respiratory chain of Escherichia coli catalyzing reduction of O2 to H2O. The enzyme is expressed under low oxygen tension; due to high affinity for O2 it is isolated mainly as a stable oxygenated complex. Direct measurement of O2 binding to heme d in the one‐electron reduced isolated enzyme gives K
d(O2) of ∼280 nM. It is possible to photolyse the heme d oxy‐complex by illumination of the enzyme for several minutes under microaerobic conditions; the light‐induced difference absorption spectrum is virtually identical to the inverted spectrum of O2 binding to heme d.