Home About us Contact
|
Home About us Contact | ||
|
|
||
Active Components (active + component)
Selected AbstractsMoS2 Single Slab as a Model for Active Component of Hydrodesulfuration Catalyst: A Quantum Chemical Study.CHEMINFORM, Issue 29 2006Part 1. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Dislocations as Active Components in Novel Silicon Devices,ADVANCED ENGINEERING MATERIALS, Issue 4 2009Martin Kittler Abstract The electrical and optical properties of dislocations in Si are reviewed, namely dislocation-related recombination and luminescence, transport of minority and majority carriers along dislocations or the electric field around dislocations. It is shown that Si wafer direct bonding allows well-controlled formation of dislocation networks, giving rise to adjustable dislocation properties. Ideas for novel Si devices utilizing dislocations as active components are presented. In particular, dislocation-based light emitters at about 1.5,µm wavelength are demonstrated. Concepts for dislocation-based conductive channels and fast FETs, manipulators of biomolecules or thermo-electric generators are sketched. [source] Micronization of the officinal component baicalin by SEDS-PA processCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2007Wen Zhi He Abstract Application of micronizing technologies in processing Chinese herbal medicines is very important to improve the forms of prepared Chinese herbal medicines and promote their therapeutic efficacy. Baicalin, a major active component of the typical Chinese herb medicine Scullateria baicallensis Georgi, was micronized using the Solution Enhanced Dispersion by Supercritical fluids though Prefilming Atomization (SEDS-PA) process with the aim of evaluating the efficiency of applying supercritical fluid precipitation technologies in Chinese herb medicine. This study has shown that acicula or rod-like baicalin crystals with Particle Size (PS) of about 20×100 ,m were successfully micronized by the SEDS-PA process to long rod-like, twisted fiber-like or fibrous net-like microparticles with PS of 0.1-2.2 ,m in width within the range of experiments performed. It was found that a substantial reduction of baicalin microparticles' sizes could lead to a marked increase of adhesions among them and subsequent microparticles agglomeration. With the increase of supercritical CO2 flow rate and the decrease of solution concentration and solution flow rate, smaller and much more agglomerated microparticles were obtained. Increasing pressure led to formation of smaller microparticles. A larger tendency of particles agglomeration was produced at a higher temperature. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Construction and Characterization of Porous SiO2/Hydrogel Hybrids as Optical Biosensors for Rapid Detection of BacteriaADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Naama Massad-Ivanir Abstract The use of a new class of hybrid nanomaterials as label-free optical biosensors for bacteria detection (E. coli K12 as a model system) is demonstrated. The hybrids combine a porous SiO2 (PSiO2) optical nanostructure (a Fabry,Pérot thin film) used as the optical transducer element and a hydrogel. The hydrogel, polyacrylamide, is synthesized in situ within the nanostructure inorganic host and conjugated with specific monoclonal antibodies (IgGs) to provide the active component of the biosensor. The immobilization of the IgGs onto the hydrogel via a biotin-streptavidin system is confirmed by fluorescent labeling experiments and reflective interferometric Fourier transform spectroscopy (RIFTS). Additionally, the immobilized IgGs maintain their immunoactivity and specificity when attached to the sensor surface. Exposure of these modified-hybrids to the target bacteria results in "direct cell capture" onto the biosensor surface. These specific binding events induce predictable changes in the thin-film optical interference spectrum of the hybrid. Preliminary studies demonstrate the applicability of these biosensors for the detection of low bacterial concentrations in the range of 103,105 cell mL,1 within minutes. [source] Nicotine induces cell proliferation, invasion and epithelial-mesenchymal transition in a variety of human cancer cell linesINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Piyali Dasgupta Abstract Cigarette smoking is strongly correlated with the onset of nonsmall cell lung cancer (NSCLC). Nicotine, an active component of cigarettes, has been found to induce proliferation of lung cancer cell lines. In addition, nicotine can induce angiogenesis and confer resistance to apoptosis. All these events are mediated through the nicotinic acetylcholine receptors (nAChRs) on lung cancer cells. In this study, we demonstrate that nicotine can promote anchorage-independent growth in NSCLCs. In addition, nicotine also induces morphological changes characteristic of a migratory, invasive phenotype in NSCLCs on collagen gel. These morphological changes were similar to those induced by the promigratory growth factor VEGF. The proinvasive effects of nicotine were mediated by ,7-nAChRs on NSCLCs. RT-PCR analysis showed that the ,7-nAChRs were also expressed on human breast cancer and pancreatic cancer cell lines. Nicotine was found to promote proliferation and invasion in human breast cancer. The proinvasive effects of nicotine were mediated via a nAChR, Src and calcium-dependent signaling pathway in breast cancer cells. In a similar fashion, nicotine could also induce proliferation and invasion of Aspc1 pancreatic cancer cells. Most importantly, nicotine could induce changes in gene expression consistent with epithelial to mesenchymal transition (EMT), characterized by reduction of epithelial markers like E-cadherin expression, ZO-1 staining and concomitant increase in levels of mesenchymal proteins like vimentin and fibronectin in human breast and lung cancer cells. Therefore, it is probable that the ability of nicotine to induce invasion and EMT may contribute to the progression of breast and lung cancers. © 2008 Wiley-Liss, Inc. [source] Bioefficacy and mode of action of rocaglamide from Aglaia elaeagnoidea (syn. A. roxburghiana) against gram pod borer, Helicoverpa armigera (Hübner)JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2004O. Koul Abstract:, Rocaglamide, a highly substituted benzofuran, was isolated and identified as the main biologically active component in Aglaia elaeagnoidea (syn. A. roxburghiana) for gram pod borer Helicoverpa armigera (Hübner). Addition of rocaglamide to an artificial diet retarded the growth of neonate larvae in a dose-dependent manner with EC50 values of 0.76 p.p.m. These values compared favourably with azadirachtin (EC50 = 0.23 p.p.m.). However, azadirachtin was apparently more potent than rocaglamide in inducing growth inhibition via oral administration to these first stadium larvae. The candidate compound was found to have LD50 and LD95 values of 0.40 and 1.02 ,g per larva, respectively, in topical application against third instar larvae 96 h post-treatment. However, these values for azadirachtin were 8.16 and 25.8 ,g per larva for the same period. This shows that azadirachtin was less effective against third instar H. armigera larvae in inducing acute toxicity via topical treatment in comparison with rocaglamide. However, severe morphological larval deformities were observed in such azadirachtin-treated larvae during the process of ecdysis. The cytotoxic nature of rocaglamide was established by evaluating dietary utilization and the results did not implicate any antifeedant effect but the toxicity-mediated effect due to reduced efficiency of conversion of ingested food. It was obvious that feeding deterrence is not the primary mode of action but a centrally mediated effect, which could be due to the induced cytotoxicity at non-specific cellular levels. [source] Preparing for "diastole": Advanced training opportunities for academic hospitalistsJOURNAL OF HOSPITAL MEDICINE, Issue 6 2006Vineet Arora MD Abstract Academic hospital medicine can be described as comprising periods of "systole," during which hospitalists provide clinical care, and periods of "diastole," the portion of a hospitalist's time spent in nonclinical activities. Far from being a period of relaxation, diastole is an active component of a hospitalist's work, the time devoted to the pursuit of career advancement. This period is a critical opportunity for career development in terms of medical research, education, quality improvement, or administration. An appropriate balance of systole and diastole may potentially prevent burnout and allow hospitalists opportunities to focus on academic advancement. Although an increasing number of residency graduates opt for a career in academic hospital medicine, few are prepared for the period of diastole. This article describes several career options in academic hospital medicine, specifically, opportunities in education, research, quality improvement, and administrative opportunities. By informing future hospitalists about the career opportunities within academic hospital medicine possible through managing their diastolic time, we hope that future generations of trainees will be better prepared to enter this field. Journal of Hospital Medicine 2006;1:368,377. © 2006 Society of Hospital Medicine. [source] Lorenzo's oil, adrenoleukodystrophy, and the blood, brain barrierJOURNAL OF NEUROCHEMISTRY, Issue 2002E. J. Murphy Adrenoleukodystrophy is a rapid, progressive demyelinating disease affecting the CNS that is characterized by large increases in plasma and tissue very long saturated fatty acids (VLCFA). Lorenzo's oil (LO), consisting of erucic (22:1 n-9) and oleic (18:1 n-9) acid in a triglyceride form, is a dietary therapy effective in reducing plasma and tissue VLCFA. Despite the decreased VLCFA, clinical studies indicated that LO failed to stop the progressive demyelination, suggesting that erucic acid, the active component of LO, did not cross the BBB. We addressed this question by infusing [14-14C] 22:1 n-9 (170 ,Ci/kg) into male rats using two different infusion paradigms. The radiotracer was infused (i.v.) into awake, adult male rats over a 10-min period or infused (i.c.v.) into the fourth ventricle over a 7-day period using an osmotic mini-pump. Brains were removed from the cranium, frozen in liquid nitrogen, lipids extracted, and separated using standard techniques. [1-14C] 20:4 n-6 was infused (i.v.) and used as a positive control. Following i.v. infusion, 0.011% of the erucic acid was extracted by the brain, compared to 0.055% of the arachidonic acid. About 60% of the brain erucic acid was found in the aqueous fraction compared to 30% for arachidonic acid. Further, erucic acid was targeted to cholesteryl ester and triacylglyceride pools, whereas arachidonic acid was targeted to phospholipid pools. In animals infused i.c.v., 0.078% of the dose was taken up and about 60% of the erucic acid was targeted to phospholipid pools. These results clearly demonstrate that erucic acid crosses the BBB, similar to arachidonic acid, and is incorporated into specific lipid pools. Acknowledgements:, This work was supported by The Myelin Project. [source] Endocannabinoids and liver disease , reviewLIVER INTERNATIONAL, Issue 5 2005Ezra Gabbay Abstract: Aims: Endocannabinoids are endogenous compounds that bind to the same receptors as tetrahydrocannabinol, the active component in marijuana and hashish. They have been found to have many physiological and patho-physiological functions, including mood alteration, control of feeding and appetite, motor and co-ordination activities, analgesia, immune modulation and gut motility. In this review we aim to elucidate current knowledge as to their role in liver physiology and disease. Methods: The major findings published to date concerning endocannabinoids and liver disease are described, and their implications with regard to understanding disease mechanisms, and the development of new treatments is considered. Results: Recently, endocannabinoids have been implicated in the hemodynamic alterations occurring in cirrhosis. These changes appear to be mediated via specific cannabinoid receptors (CB1) on splanchnic and hepatic vascular endothelium. Plasma levels of endocannabinoids also seem to be elevated in hepatitis, and are involved in apoptosis of hepatocytes by a membrane mechanism not related to a specific receptor. Other studies suggest a beneficial role for cannabinoids in reducing the inflammation of experimental hepatitis. In an animal model of acute hepatic failure, both endocannabinoids and the antagonist to the CB1 receptor have been found to have a beneficial effect on neurological and cognitive function. Conclusions: Endocannabinoids appear to be involved in several aspects of acute and chronic liver disease, including vascular changes, modulation of inflammatory process and neurological function, Further research may provide new insights into the pathophysiology of liver disease, as well as a basis for novel treatment modalities. [source] Allicin, the active component of garlic, prevents immune-mediated, concanavalin A-induced hepatic injury in miceLIVER INTERNATIONAL, Issue 3 2005Rafael Bruck Abstract: Background/Aim: Allicin, the immunologically active component of garlic, has been found to affect oxidative stress and immune response in several experimental systems. In the present study, we examined the ability of allicin to prevent immune-mediated, concanavalin A (Con A)-induced liver damage in mice. Methods: Mice were pretreated with allicin for 7 days before their inoculation with Con A (15 mg/kg). The serum levels of liver enzymes and liver histology were examined 24 h after Con A administration. The effect of Con A and allicin on serum levels of tumor necrosis factor-, (TNF-,) and nuclear factor-,B (NF-,B) activation in the liver were examined 2 h after Con A administration, in a separate group of rats, and the effect of allicin on Con A-induced expression of inducible nitric oxide synthase (iNOS) was determined by western blot analysis 24 h after Con A injection. Results: The histopathologic damage in the mouse livers, and the Con A-induced increase of aminotransferases and TNF-, were markedly inhibited in the mice pretreated with allicin before Con A injection (P<0.01). NF-,B binding activity to the nucleus, which increased 2 h after Con A administration, was attenuated by allicin. The expression of iNOS protein which was induced following Con A administration was significantly attenuated by allicin. In vitro studies showed that allicin inhibited TNF-,-mediated T cell adhesion to extracellular matrix components and to endothelial cells. Allicin also inhibited TNF-,-mediated intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression on human vascular endothelial cells. Conclusions: This study demonstrates that immune-mediated liver damage in mice can be prevented by allicin, probably because of its immunomodulatory effects on T cells and adhesion molecules and inhibition of NF-,B activation. [source] Recombination and lineage-specific gene loss in the aflatoxin gene cluster of Aspergillus flavusMOLECULAR ECOLOGY, Issue 23 2009GEROMY G. MOORE Abstract Aflatoxins produced by Aspergillus flavus are potent carcinogens that contaminate agricultural crops. Recent efforts to reduce aflatoxin concentrations in crops have focused on biological control using nonaflatoxigenic A. flavus strains AF36 (=NRRL 18543) and NRRL 21882 (the active component of afla-guard®). However, the evolutionary potential of these strains to remain nonaflatoxigenic in nature is unknown. To elucidate the underlying population processes that influence aflatoxigenicity, we examined patterns of linkage disequilibrium (LD) spanning 21 regions in the aflatoxin gene cluster of A. flavus. We show that recombination events are unevenly distributed across the cluster in A. flavus. Six distinct LD blocks separate late pathway genes aflE, aflM, aflN, aflG, aflL, aflI and aflO, and there is no discernable evidence of recombination among early pathway genes aflA, aflB, aflC, aflD, aflR and aflS. The discordance in phylogenies inferred for the aflW/aflX intergenic region and two noncluster regions, tryptophan synthase and acetamidase, is indicative of trans-species evolution in the cluster. Additionally, polymorphisms in aflW/aflX divide A. flavus strains into two distinct clades, each harbouring only one of the two approved biocontrol strains. The clade with AF36 includes both aflatoxigenic and nonaflatoxigenic strains, whereas the clade with NRRL 21882 comprises only nonaflatoxigenic strains and includes all strains of A. flavus missing the entire gene cluster or with partial gene clusters. Our detection of LD blocks in partial clusters indicates that recombination may have played an important role in cluster disassembly, and multilocus coalescent analyses of cluster and noncluster regions indicate lineage-specific gene loss in A. flavus. These results have important implications in assessing the stability of biocontrol strains in nature. [source] A biochemical analysis of the interaction of DNA gyrase with the bacteriophage Mu, pSC101 and pBR322 strong gyrase sites: the role of DNA sequence in modulating gyrase supercoiling and biological activityMOLECULAR MICROBIOLOGY, Issue 1 2003Mark Oram Summary Replication of bacteriophage Mu DNA, a process requiring efficient synapsis of the prophage ends, takes place within the confines of the Escherichia coli nucleoid. Critical to ensuring rapid synapsis is the function of the SGS, a strong gyrase site, located at the centre of the Mu genome. Replacement of the SGS by the strong gyrase sites from pSC101 or pBR322 fails to support efficient prophage replication. To probe the unique SGS properties we undertook a biochemical analysis of the interaction of DNA gyrase with the Mu SGS, pSC101 and pBR322 sites. In binding and cleavage assays the order of efficacy was pSC101 > Mu SGS >> pBR322. However, in supercoiling assays the Mu SGS (cloned into pUC19) exhibited a strong enhancement of gyrase-catalysed supercoiling over pUC19 alone; the pSC101 site showed none and the pBR322 site gave a moderate improvement. Most striking was the Mu SGS-dependent increase in processivity of the gyrase reaction. This highly processive supercoiling coupled with efficient binding may account for the unique biological properties of the SGS. The results emphasize the importance of the DNA substrate as an active component in modulating the gyrase supercoiling reaction, and in determining the biological roles of specialized gyrase sites. [source] Soybean Foods and Their Benefits: Potential Mechanisms of ActionNUTRITION REVIEWS, Issue 8 2005Adetayo O. Omoni MSc Isoflavones have been proposed to be the active component responsible for the beneficial effects of soybean foods, and appear to work in conjunction with the proteins to protect against cancer, cardiovascular disease, and osteoporosis. Most of the research activities on the benefits of soybean foods have focused on the role these isoflavones play in disease prevention or treatment; however, there is also some evidence that the benefits are attributable to certain peptides or protein fractions from soybeans. This review will focus on some of the potential mechanisms whereby soybeans exert their protective effects against heart disease, cancer, and osteoporosis. [source] After-effects of near-threshold stimulation in single human motor axonsTHE JOURNAL OF PHYSIOLOGY, Issue 3 2005Hugh Bostock Subthreshold electrical stimuli can generate a long-lasting increase in axonal excitability, superficially resembling the phase of superexcitability that follows a conditioning nerve impulse. This phenomenon of ,subthreshold superexcitability' has been investigated in single motor axons in six healthy human subjects, by tracking the excitability changes produced by conditioning stimuli of different amplitudes and waveforms. Near-threshold 1 ms stimuli caused a mean decrease in threshold at 5 ms of 22.1 ± 6.0% (mean ±s.d.) if excitation occurred, or 6.9 ± 2.6% if excitation did not occur. The subthreshold superexcitability was maximal at an interval of about 5 ms, and fell to zero at 30 ms. It appeared to be made up of two components: a passive component linearly related to conditioning stimulus amplitude, and a non-linear active component. The active component appeared when conditioning stimuli exceeded 60% of threshold, and accounted for a maximal threshold decrease of 2.6 ± 1.3%. The passive component was directly proportional to stimulus charge, when conditioning stimulus duration was varied between 0.2 and 2 ms, and could be eliminated by using triphasic stimuli with zero net charge. This change in stimulus waveform had little effect on the active component of subthreshold superexcitability or on the ,suprathreshold superexcitability' that followed excitation. It is concluded that subthreshold superexcitability in human motor axons is mainly due to the passive electrotonic effects of the stimulating current, but this is supplemented by an active component (about 12% of suprathreshold superexcitability), due to a local response of voltage-dependent sodium channels. [source] An Immunomodulatory Role for Follistatin-Like 1 in Heart Allograft TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2008J. B. Le Luduec Donor-specific tolerance to heart allografts in the rat can be achieved by donor-specific blood transfusions (DST) before transplantation. We have previously reported that this tolerance is associated with strong leukocyte infiltration, and that host CD8+ T cells and TGF, are required. In order to identify new molecules involved in the induction phase of tolerance, we compared tolerated and rejected heart allografts (suppressive subtractive hybridization) 5 days after transplantation. We identified overexpression of Follistatin-like 1 (FSTL1) transcript in tolerated allografts compared to rejected allografts or syngeneic grafts. We show that FSTL1 is overexpressed during both the induction and maintenance phase of tolerance, and appears to be specific to the tolerance model induced by DST. Analysis of graft-infiltrating cells revealed predominant expression of FSTL1 in CD8+ T cells from tolerated grafts, and depletion of these cells prior to transplantation abrogated FSTL1 expression and heart allograft survival. Moreover, overexpression of FSTL1 by adenovirus gene transfer in vivo significantly prolonged allograft survival in association with inhibition of the proinflammatory cytokines, IL6, IL17 A and IFN,. Taken together, these results suggest that FSTL1 could be an active component of the mechanisms mediating heart allograft tolerance. [source] Topical application of acidified nitrite to the nail renders it antifungal and causes nitrosation of cysteine groups in the nail plateBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2007M.J. Finnen Summary Background, Topical treatment of nail diseases is hampered by the nail plate barrier, consisting of dense cross-linked keratin fibres held together by cysteine-rich proteins and disulphide bonds, which prevents penetration of antifungal agents to the focus of fungal infection. Acidified nitrite is an effective treatment for tinea pedis. It releases nitric oxide (NO) and other NO-related species. NO can react with thiol (-SH) groups to form nitrosothiols (-SNO). Objectives, To determine whether acidified nitrite can penetrate the nail barrier and cure onychomycosis, and to determine whether nitrosospecies can bind to the nail plate. Methods, Nails were treated with a mixture of citric acid and sodium nitrite in a molar ratio of 0·54 at either low dose (0·75%/0·5%) or high dose (13·5%/9%). Immunohistochemistry, ultraviolet-visible absorbance spectroscopy and serial chemical reduction of nitrosospecies followed by chemiluminescent detection of NO were used to measure nitrosospecies. Acidified nitrite-treated nails and the nitrosothiols S-nitrosopenicillamine (SNAP) and S-nitrosoglutathione (GSNO) were added to Trichophyton rubrum and T. mentagrophytes cultures in liquid Sabouraud medium and growth measured 3 days later. Thirteen patients with positive mycological cultures for Trichophyton or Fusarium species were treated with topical acidified nitrite for 16 weeks. Repeat mycological examination was performed during this treatment time. Results, S-nitrothiols were formed in the nail following a single treatment of low- or high-dose sodium nitrite and citric acid. Repeated exposure to high-dose acidified nitrite led to additional formation of N-nitrosated species. S-nitrosothiol formation caused the nail to become antifungal to T. rubrum and T. mentagrophytes. Antifungal activity was Cu2+ sensitive. The nitrosothiols SNAP and GSNO were also found to be antifungal. Topical acidified nitrite treatment of patients with onychomycosis resulted in > 90% becoming culture negative for T. rubrum. Conclusions, Acidified nitrite cream results in the formation of S-nitrosocysteine throughout the treated nail. Acidified nitrite treatment makes a nail antifungal. S-nitrosothiols, formed by nitrosation of nail sulphur residues, are the active component. Acidified nitrite exploits the nature of the nail barrier and utilizes it as a means of delivery of NO/nitrosothiol-mediated antifungal activity. Thus the principal obstacle to therapy in the nail becomes an effective delivery mechanism. [source] Caffeic acid phenethyl ester modulates Helicobacter pylori -induced nuclear factor-kappa B and activator protein-1 expression in gastric epithelial cellsBRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2005Mohamed M M Abdel-Latif Caffeic acid phenethyl ester (CAPE), an active component of propolis from honeybee hives (honeybee resin), has anti-inflammatory, anti-carcinogenic and anti-bacterial properties. This study was designed to investigate the anti-inflammatory effects of CAPE on Helicobacter pylori -induced NF- ,B and AP-1 in the gastric epithelial cell line AGS. Electrophoretic mobility shift assay was used to measure NF- ,B- and AP-1-DNA binding activity. Western blotting was used to detect I,B- , and COX-2 expression in AGS cells cocultured with H. pylori. The antiproliferative effect of CAPE was measured by MTT assay. Our results showed that caffeic phenethyl ester inhibits H. pylori -induced NF- ,B and AP-1 DNA-binding activity in a dose (0.1,25 ,g ml,1,0.35,88 ,M) and time- (15,240 min) dependent manner in AGS cells. Maximum inhibition by CAPE was observed at concentrations of 25 ,g ml,1 (,88 ,M) CAPE prevented H. pylori - and cytokine-induced degradation of I,B- , protein. Pretreatment of AGS cells with CAPE also blocked cytokine- and mitogen-induced NF- ,B and AP-1 expression. Furthermore, CAPE suppressed H. pylori -induced cell proliferation and production of the cytokines TNF- , and IL-8. In addition, CAPE blocked H. pylori -induced COX-2 expression. The inhibition of such transcription by CAPE could result in suppression of many genes during H. pylori -induced inflammation, and also provide new insights into the anti-cancer and anti-inflammatory properties of CAPE. British Journal of Pharmacology (2005) 146, 1139,1147. doi:10.1038/sj.bjp.0706421 [source] (,)-Epigallocatechin gallate suppresses the growth of human hepatocellular carcinoma cells by inhibiting activation of the vascular endothelial growth factor,vascular endothelial growth factor receptor axisCANCER SCIENCE, Issue 10 2009Yohei Shirakami The receptor tyrosine kinase vascular endothelial growth factor (VEGF) receptor (VEGFR) plays an important role in tumor angiogenesis of hepatocellular carcinoma (HCC). (,)-Epigallocatechin gallate (EGCG), the major biologically active component of green tea, inhibits growth in a variety of human cancer cells by inhibiting the activation of several types of receptor tyrosine kinases. In this study, we examined the effects of EGCG on the activity of the VEGF,VEGFR axis in human HCC cells. The levels of total and phosphorylated (i.e. activated) form of VEGFR-2 protein (p-VEGFR-2) were observed to increase in a series of human HCC cell lines in comparison to the Hc normal human hepatocytes. EGCG preferentially inhibited the growth of HuH7 HCC cells, which express constitutive activation of the VEGF,VEGFR axis, in comparison to Hc cells. Treatment of HuH7 cells with EGCG caused a time- and dose-dependent decrease in the expression of VEGFR-2 and p-VEGFR-2 proteins. The production of VEGF from HuH7 cells was reduced by treatment with EGCG. Drinking of EGCG significantly inhibited the growth of HuH7 xenografts in nude mice and this was associated with inhibition of the activation of VEGFR-2 and its related downstream signaling molecules, including ERK and Akt. EGCG drinking also decreased the expression of Bcl-xL protein and VEGF mRNA in the xenografts. These findings suggest that EGCG can exert, at least in part, its growth-inhibitive effect on HCC cells by inhibiting the VEGF,VEGFR axis. EGCG might therefore be useful in the treatment of HCC. (Cancer Sci 2009; 100: 1957,1962) [source] The effects of the caffeic acid phenethyl ester (CAPE) on erythrocyte membrane damage after hind limb ischaemia,reperfusionCELL BIOCHEMISTRY AND FUNCTION, Issue 5 2004Lülüfer Tamer Abstract Reactive oxygen species have been implicated in pathogenesis injury after ischaemia,reperfusion (I/R). Caffeic Acid Phenethyl Ester (CAPE), an active component of honeybee propolis extract, exhibits antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effects of CAPE on erythrocyte membrane damage after hind limb I/R. Rats were divided into two groups: I/R and I/R with CAPE pre-treatment. They were anaesthetized with intramuscular ketamine 100,mg,kg,1. A 4-h I/R period was performed on the right hind limb of all animals. In the CAPE-treated group, animals received CAPE 10,,m by intraperitoneal injection 1,h before the reperfusion. At the end of the reperfusion period, a midsternotomy was performed. A 5-ml blood sample was withdrawn from the ascending aorta for biochemical assays. Serum and erythrocyte membrane MDA levels were significantly lower in the CAPE-treated group when compared to the I/R group (,p,=,0.001 and p<0.001, respectively). Erythrocyte membrane Na+ -K+ ATPases activity in the CAPE-treated group was significantly higher than the I/R group (,p<0.001). In conclusion, CAPE seems to be effective in protecting against oxidative stress. Therefore, we suggest that in order to decrease I/R injury, pre-administration of CAPE may be a promising agent for a variety of conditions associated with I/R. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effects of caffeic acid phenethyl ester and alpha-tocopherol on reperfusion injury in rat brainCELL BIOCHEMISTRY AND FUNCTION, Issue 3 2003M. Kemal Irmak Abstract Oxygen-derived free radicals have been implicated in the pathogenesis of cerebral injury after ischaemia,reperfusion. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant properties. The purpose of the present study was to investigate the effects of ischaemia and subsequent reperfusion on rat brain and to investigate the effects of two free radical scavengers, CAPE and alpha-tocopherol, on this in vivo model of cerebral injury. Ischaemia was induced by bilateral occlusion of the carotid arteries for 20,min and reperfusion was achieved by releasing the occlusion to restore the circulation for 20,min. Control rats underwent a sham operation. CAPE at 10,,;mol,kg,1 or alpha-tocopherol at 25,,mol,kg,1 was administered intraperitoneally before reperfusion. Reperfusion led to significant increase in the activity of xanthine oxidase and higher malondialdehyde levels in the brain. Acute administration of both CAPE and alpha-tocopherol suppressed ischaemia,reperfusion-induced cerebral lipid peroxidation and injury, but CAPE seems to offer a better therapeutic advantage over alpha-tocopherol. Copyright © 2003 John Wiley & Sons, Ltd. [source] Caffeic acid phenethyl ester changes the indices of oxidative stress in serum of rats with renal ischaemia,reperfusion injuryCELL BIOCHEMISTRY AND FUNCTION, Issue 4 2001Hüseyin Özyurt Abstract Oxygen-derived free radicals have been implicated in the pathogenesis of renal injury after ischaemia,reperfusion. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant properties. To investigate whether treatment with either CAPE or alpha-tocopherol modifies the levels of the endogenous indices of oxidant stress, we examined their effects on an in vivo model of renal ischaemia,reperfusion injury in rats. CAPE at 10,,mol,kg,1 or alpha-tocopherol at 10,mg,kg,1 was administered intraperitoneally before reperfusion. Acute administration of both CAPE and alpha-tocopherol altered the indices of oxidative stress differently in renal ischaemia,reperfusion injury. Copyright © 2001 John Wiley & Sons, Ltd. [source] Cytotoxicity of lavender oil and its major components to human skin cellsCELL PROLIFERATION, Issue 3 2004A. Prashar Concerns are building about the potential for irritant or allergenic skin reactions with the use of lavender oil. This study has demonstrated that lavender oil is cytotoxic to human skin cells in vitro (endothelial cells and fibroblasts) at a concentration of 0.25% (v/v) in all cell types tested (HMEC-1, HNDF and 153BR). The major components of the oil, linalyl acetate and linalool, were also assayed under similar conditions for their cytotoxicity. The activity of linalool reflected that of the whole oil, indicating that linalool may be the active component of lavender oil. Linalyl acetate cytotoxicity was higher than that of the oil itself, suggesting suppression of its activity by an unknown factor in the oil. Membrane damage is proposed as the possible mechanism of action. [source] Consideration of the Effect of Irregular Catalytic Active Component Distributions in Mesopores , Extension of a Model for Wall Catalyzed Reactions in Microchannel ReactorsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2003B. Platzer Abstract Data available from the literature and experimental results have shown that the distribution of the catalytic active components can be irregular already for fresh catalysts. The determination of the local concentrations of the catalytic active components using wavelength dispersive X-ray spectroscopy confirms this for microstructured wafers used in microchannel reactors. Considering this nonuniform distribution, the used model gives the relation between the local concentration profiles of the reactants inside the pores and the product yield in the entire pore. These results were used in an equation for the diffusion flux at the pore mouth, which is useful for a microchannel model developed in a recent paper [1]. The theoretical considerations deal with cylindrical pores with known reactant concentrations at the pore mouth and known distribution of the catalytic active component within the pore. Beside numerical results, some analytical solutions with low mathematical expense, applicable to special cases, are discussed. The nonconsideration of the irregular distribution of the catalytic active component can be the reason for difficulties during the extrapolation of experimental results to slightly different conditions and can have a great influence on the reaction results. The regarded examples are typical of wall-catalyzed reactions in microchannel reactors with mesopores. [source] Surface Composition of Materials Used as Catalysts for Methanol Steam Reforming: A Theoretical Study,CHEMPHYSCHEM, Issue 8 2006Kok Hwa Lim Dr. Abstract PdZn (1:1) alloy is assumed to be the active component of a promising catalyst for methanol steam reforming. Using density functional calculations on periodic supercell slab models, followed by atomistic thermodynamics modeling, we study the chemical composition of the surfaces PdZn(111) and, as a reference, Cu(111) in contact with water and hydrogen at conditions relevant to methanol steam reforming. For the two surfaces, we determine similar maximum adsorption energies for the dissociative adsorption of H2, O2, and the molecular adsorption of H2O. These reactions are calculated to be exothermic by about ,40, ,320, and ,20 kJ,mol,1, respectively. Using a thermodynamic analysis based on theoretically predicted adsorption energies and vibrational frequencies, we determine the most favorable surface compositions for given pressure windows. However, surface energy plots alone cannot provide quantitative information on individual coverages in a system of coupled adsorption reactions. To overcome this limitation, we employ a kinetic model, from which equilibrium surface coverages of H, O, OH, and H2O are derived. We also discuss the sensitivity of our results and the ensuing conclusions with regard to the model surfaces employed and the inaccuracies of our computational method. Our kinetic model predicts surfaces of both materials, PdZn and Cu, to be essentially adsorbate-free already from very low values of the partial pressure of H2. The model surfaces PdZn(111) and Cu(111) are predicted to be free of water-related adsorbates for a partial H2 pressure greater than 10,8 and 10,5 atm, respectively. [source] Ceria-Based Solid Catalysts for Organic ChemistryCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 6 2010Laurence Vivier Dr. Abstract Ceria has been the subject of thorough investigations, mainly because of its use as an active component of catalytic converters for the treatment of exhaust gases. However, ceria-based catalysts have also been developed for different applications in organic chemistry. The redox and acid,base properties of ceria, either alone or in the presence of transition metals, are important parameters that allow to activate complex organic molecules and to selectively orient their transformation. Pure ceria is used in several organic reactions, such as the dehydration of alcohols, the alkylation of aromatic compounds, ketone formation, and aldolization, and in redox reactions. Ceria-supported metal catalysts allow the hydrogenation of many unsaturated compounds. They can also be used for coupling or ring-opening reactions. Cerium atoms can be added as dopants to catalytic system or impregnated onto zeolites and mesoporous catalyst materials to improve their performances. This Review demonstrates that the exceptional surface (and sometimes bulk) properties of ceria make cerium-based catalysts very effective for a broad range of organic reactions. [source] Postnatal and postprandial changes in plasma concentrations of glicentin in term and preterm infantsACTA PAEDIATRICA, Issue 10 2003R Tadokoro Aim: To examined the changes in basal plasma concentrations of glicentin in developing children and the postnatal and postprandial changes in plasma glicentin levels in infants. Methods: Glicentin, an active component of enteroglucagon, is considered to have a significant trophic action on the intestinal mucosa. Fasting plasma concentrations of glicentin in healthy children and in term and preterm infants were measured before and 30 min after feeding during the first 14 d of life. Results: Plasma basal concentrations of glicentin in children under 1 y of age were significantly higher than those in children aged 1 to 15 y. Plasma basal concentrations of glicentin at 5 or 6 d (2496 and 2190 pg/ml) and at 14 d (2987 and 2817 pg/ml) after birth were significantly higher than those at 1 or 2 d (1098 and 1240 pg/ml) after birth in normal birthweight (NBW) and low-birthweight (LBW) infants. There was no significant difference in the glicentin level between infants at 1 or 2 d (1864 pg/ml) and at 5 or 6 d (1910 pg/ml) after birth in very-low birthweight (VLBW) infants, but the levels at 14 d (3310 pg/ml) after birth were significantly higher than either of those levels. Plasma glicentin concentrations after feeding were significantly higher than those before feeding at 1 or 2 d and at 5 or 6 d after birth in NBW and LBW infants, but a significant increase in the plasma glicentin level after feeding was first observed at 14 d after birth in VLBW infants. There were no significant differences in the basal plasma (2401 and 2718 pg/ml) and postprandial (3007 and 3912 pg/ml) glicentin levels between breastfed and formula-fed infants. Conclusion: The results of the study suggest that glicentin may play an important role in intestinal mucosal growth in the early period of life, although its role in VLBW infants should be further investigated. [source] Coupling of solid-phase microextraction continuous bed (monolithic) capillaries with capillary zone electrophoresis for direct analysis of drugs in biological fluids,ELECTROPHORESIS, Issue 8 2008Reda Jarmalavi Abstract Hyperlink robust biocompatible solid-phase microextraction (SPME) devices were prepared using continuous bed (monolithic) restricted-access media (RAM) as the SPME capillary insert. The RAM-based SPME approach was able to simultaneously separate proteins from a biological sample, while directly extracting the active components of caffeine, paracetamol and acetylsalicylic acid from the drug NeoCitramonum. The devices were interfaced with a CZE system and fully automated analysis for sample preconcentration, desorption, separation and quantification of analytes was evaluated. Comparative study of in-line coupled SPME,CZE using RAM and RP capillary inserts was carried out. Using an SPME (RAM) insert, the calculated caffeine, paracetamol and acetylsalicylic acid LODs in a bovine plasma sample were 0.3, 0.8 and 1.9,ng/mL, respectively. [source] The role of colonic metabolism in lactose intoleranceEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2008T. He ABSTRACT Lactose maldigestion and intolerance affect a large part of the world population. The underlying factors of lactose intolerance are not fully understood. In this review, the role of colonic metabolism is discussed, i.e. fermentation of lactose by the colonic microbiota, colonic processing of the fermentation metabolites and how these processes would play a role in the pathophysiology of lactose intolerance. We suggest that the balance between the removal and production rate of osmotic,active components (lactose, and intermediate metabolites, e.g. lactate, succinate, etc.) in the colon is a key factor in the development of symptoms. The involvement of the colon may provide the basis for designing new targeted strategies for dietary and clinical management of lactose intolerance. [source] Dislocations as Active Components in Novel Silicon Devices,ADVANCED ENGINEERING MATERIALS, Issue 4 2009Martin Kittler Abstract The electrical and optical properties of dislocations in Si are reviewed, namely dislocation-related recombination and luminescence, transport of minority and majority carriers along dislocations or the electric field around dislocations. It is shown that Si wafer direct bonding allows well-controlled formation of dislocation networks, giving rise to adjustable dislocation properties. Ideas for novel Si devices utilizing dislocations as active components are presented. In particular, dislocation-based light emitters at about 1.5,µm wavelength are demonstrated. Concepts for dislocation-based conductive channels and fast FETs, manipulators of biomolecules or thermo-electric generators are sketched. [source] Mesoporous Systems for the Preparation of Ordered Magnetic Nanowire Arrays,ADVANCED ENGINEERING MATERIALS, Issue 4 2005A. Eliseev Some tendencies in data storage technologies based on magnetic nanostructures are discussed and a novel approach to anisotropic magnetic nanoparticles which can be used as an active components of magnetic storage media is proposed by the authors [source] | ||||||||||||||||||||||||||||||||||||||||