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Results Implied (result + implied)
Selected AbstractsCentral and peripheral cardiovascular adaptations to exercise in endurance-trained childrenACTA PHYSIOLOGICA, Issue 2 2002S. NOTTIN ABSTRACT Stroke volume (SV) response to exercise depends on changes in cardiac filling, intrinsic myocardial contractility and left ventricular afterload. The aim of the present study was to identify whether these variables are influenced by endurance training in pre-pubertal children during a maximal cycle test. SV, cardiac output (Doppler echocardiography), left ventricular dimensions (time,movement echocardiography) as well as arterial pressure and systemic vascular resistances were assessed in 10 child cyclists (VO2max: 58.5 ± 4.4 mL min,1 kg,1) and 13 untrained children (UTC) (VO2max: 45.9 ± 6.7 mL min,1 kg,1). All variables were measured at the end of the resting period, during the final minute of each workload and during the last minute of the progressive maximal aerobic test. At rest and during exercise, stroke index was significantly higher in the child cyclists than in UTC. However, the SV patterns were strictly similar for both groups. Moreover, the patterns of diastolic and systolic left ventricular dimensions, and the pattern of systemic vascular resistance of the child cyclists mimicked those of the UTC. SV patterns, as well as their underlying mechanisms, were not altered by endurance training in children. This result implied that the higher maximal SV obtained in child cyclists depended on factors influencing resting SV, such as cardiac hypertrophy, augmented myocardium relaxation properties or expanded blood volume. [source] Calnexin inhibits thermal aggregation and neurotoxicity of prion proteinJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2010Wenxi Wang Abstract Prion diseases are fatal neurodegenerative disorder associated with the conversion of the cellular isoform of the prion protein (PrPC) into the infectious scrapie isoform (PrPSc). Deposition of misfolded prion proteins (PrP) on certain regions of brain can result in prion diseases. As a membrane-bound chaperone of the endoplasmic reticulum (ER), calnexin ensures the proper folding and quality control of newly synthesized proteins. Using purified components in vitro, calnexin associated with many proteins and suppresses their thermal aggregation effectively. We for the first time analyzed PrP-calnexin interaction. The immunoprecipitation, confocal microscope and native polyacrylamide-gel electrophoresis results indicated that calnexin could bind PrP both in vitro and in vivo. The turbidity result showed that calnexin could supress thermal aggregation of PrP. MTT, flow cytometry (FCM) and caspase activity studies demonstrated that calnexin prevent caspase-3-mediated cytotoxicity induced by PrP. These results implied that calnexin is potentially beneficial for the resistance of prion diseases. J. Cell. Biochem. 111: 343,349, 2010. © 2010 Wiley-Liss, Inc. [source] Xanthophyll Cycle and Inactivation of Photosystem II Reaction Centers Alleviating Reducing Pressure to Photosystem I in Morning Glory Leaves under Short-term High IrradianceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 7 2007Xin-Guo Li Abstract Under 30-min high irradiance (1500 ,mol m,2 s,1), the roles of the xanthophyll cycle and D1 protein turnover were investigated through chlorophyll fluorescence parameters in morning glory (Ipomoea setosa) leaves, which were dipped into water, dithiothreitol (DTT) and lincomycin (LM), respectively. During the stress, both the xanthophyll cycle and D1 protein turnover could protect PSI from photoinhibition. In DTT leaves, non-photochemical quenching (NPQ) was inhibited greatly and the oxidation level of P700 (P700+) was the lowest one. However, the maximal photochemical efficiency of PSII (Fv/Fm) in DTT leaves was higher than that of LM leaves and was lower than that of control leaves. These results suggested that PSI was more sensitive to the loss of the xanthophyll cycle than PSII under high irradiance. In LM leaves, NPQ was partly inhibited, Fv/Fm was the lowest one among three treatments under high irradiance and P700+ was at a similar level as that of control leaves. These results implied that inactivation of PSII reaction centers could protect PSI from further photoinhibition. Additionally, the lowest of the number of active reaction centers to one inactive reaction center for a PSII cross-section (RC/CSo), maximal trapping rate in a PSII cross-section (TRo/CSo), electron transport in a PSII cross-section (ETo/CSo) and the highest of 1-qP in LM leaves further indicated that severe photoinhibition of PSII in LM leaves was mainly induced by inactivation of PSII reaction centers, which limited electrons transporting to PSI. However, relative to the LM leaves the higher level of RC/CSo, TRo/CSo, Fv/Fm and the lower level of 1-qP in DTT leaves indicated that PSI photoinhibition was mainly induced by the electron accumulation at the PSI acceptor side, which induced the decrease of P700+ under high irradiance. [source] Fusion characteristics of rigid PVC/wood-flour composites by torque rheometryJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2007Laurent M. Matuana This study was aimed at examining the effects of wood flour contents, wood species (softwood vs. hardwood), and particle size on the fusion characteristics (fusion time, fusion temperature, fusion torque, and fusion energy) of rigid PVC/wood-flour composites in a torque rheometer. Neat rigid PVC exhibited one fusion peak, whereas the addition of wood flour into the PVC matrix led to two fusion peaks. Increased wood flour content caused a significant increase in the time, temperature, and energy at which fusion between the primary particles started, thereby leading to increased fusion torque, irrespective of the wood flour species. These results implied that rigid PVC filled with wood flour must be processed at higher temperatures than neat resin. Although fusion characteristics of the composites were influenced by the wood species, a clear trend between softwood and hardwood species could not be established. However, finer particles fused more quickly and needed less energy than coarse ones. J. VINYL ADDIT. TECHNOL., 13:7,13, 2007. © 2007 Society of Plastics Engineers. [source] Expression pattern of keratin subclasses in pancreatoblastoma with special emphasis on squamoid corpusclesPATHOLOGY INTERNATIONAL, Issue 6 2005Shigeo Nishimata Expression patterns of keratins (K), both simple epithelia-type (K7, K8, K18, K19) and complex/stratified epithelia-type (K1, K4, K5/6, K10, K13, K14, K15, K16, K17), and epithelial membrane antigen (EMA) were immunohistochemically studied in six pancreatoblastomas (PBL). In all six tumors, areas with overt acinar differentiation (AA), solid areas without any specific differentiation (SO), and squamoid corpuscles (SC) were diffusely positive for K8, K18, and K19. The AA and SO in all the tumors were diffusely positive for K7, but the SC were negative or displayed only scattered reactivity for K7. In three tumors, the AA and the SC showed scattered reactivity for K5/6. No reactivity for other complex/stratified epithelia-type K was found in any of the examined tumor. All tumors were reactive for EMA with consistent predominancy in the SC. Ultrastructurally, well-developed desmosome-tonofilament complexes were only partially observed in tumor cells comprising the SC. These results implied that (i) the SC usually lack a character of complete squamous metaplasia; and (ii) the SC have a characteristic phenotype (K8/K18/K19/EMA-positive, K7-negative or scatteredly positive) that can potentially be useful to delineate the SC in PBL. [source] Azathioprine hepatotoxicity and the protective effect of liquorice and glycyrrhizic acidPHYTOTHERAPY RESEARCH, Issue 8 2006Yue-Ting Wu Abstract This study aimed to evaluate the responses of human hepatocytes to azathioprine hepatotoxicity in comparison with the well-studied azathioprine hepatotoxicity in rat hepatocytes and the effects of protective agents to suppress azathioprine hepatotoxicity. Azathioprine presented its hepatotoxicity at clinically relevant concentrations (lower than 10 µm) in primary rat hepatocytes after 48 h of treatment as shown by a severe decrease in cell viability as well as intracellular GSH depletion. However, primary human hepatocytes exhibited only significant intracellular GSH depletion after treatment with azathioprine at these clinically relevant concentrations, while a reduction in cell viability by 29% was only evidenced after 48 h of treatment with azathioprine at the high concentration of 50 µm. In addition, a monolayer culture of primary rat hepatocytes was used as an in vitro model to examine the protective effects of antihepatotoxic drugs including glutathione (GSH), N-acetylcysteine (NAC, a GSH precursor), liquorice and glycyrrhizic acid (GA), a major bioactive component of liquorice, against hepatotoxicity of 1 µm azathioprine. It was found that both liquorice and GA showed substantial protection according to assays of cell viability and intracellular GSH, while neither GSH nor NAC had such a protective function. Similarly, GA protected human hepatocytes from intracellular GSH depletion on exposure to 1 µm azathioprine. These results implied that GA or liquorice could be considered as potent protection agents against azathioprine hepatotoxicity. Copyright © 2006 John Wiley & Sons, Ltd. [source] Structure and properties of multi-walled carbon nanotubes/polyethylene nanocomposites synthesized by in situ polymerization with supported Cp2ZrCl2 catalystPOLYMER COMPOSITES, Issue 3 2010Shiyun Li Multi-walled carbon nanotubes (MWCNTs)/polyethylene (PE) nanocomposites were prepared via in situ polymerization with MWCNTs supported Bis- (cyclopentadienyl) zirconium dichloride (Cp2ZrCl2) catalyst. X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FESEM) results implied that Cp2ZrCl2 catalyst was immobilized in the surface of the MWCNTs supports via a bridge of methylaluminoxane (MAO). The efficient dispersion of MWCNTs in PE matrix and the strong compressive forces associated with PE on the MWCNTs were demonstrated by means of transmission electron microscope (TEM), FESEM and Raman spectra. With introducing 0.2 wt% MWCNTs, both the tensile strength and elongation of MWCNTs/PE nanocomposite were improved by factors of 1.6 (from 29 to 45 MPa) and 1.5 (from 909% to 1360%) comparing with the pure PE, respectively. Morphology observation of fractured surface revealed that the PE firmly adhered to the nanotubes, which was responsible for the significant improvement of the mechanical properties of nanocomposites. Thermal stabilities of the nanocomposites were significantly improved. In addition, the MWCNTs/PE nanocomposites showed very high ultraviolet (UV) shielding property, which could increase photooxidative stability of the PE. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Oxidative Damage of Biomolecules in Mouse Liver Induced by Morphine and Protected by AntioxidantsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2004Yun-Tao Zhang The oxidative damage of DNA as measured by single cell electrophoresis and high-performance liquid chromatography equipped with electrochemical and UV detection, the protein carbonyl content was measured by 2,4-dinitrophenylhydrazine method, and the malondialdehyde content was measured by the HPLC method. The activities of antioxidative enzymes, superoxide dismutase, catalase and glutathione peroxidase, and the activity of alanine aminotransferase were assayed by spectrophotometer method. Glutathione and oxidized glutathione were detected by fluorescence spectrophotometer method. All the indexes of oxidative damage, such as 8-OHdG, protein carbonyl group and malondialdehyde content, and the activity of alanine aminotransferase (n=27) increased significantly compared to those of control (n=27) (P<0.01) in livers of morphine-administered alone mice, while the indexes related with the in vivo antioxidative capacity, such as the ratio of glutathione and oxidized glutathione, activities of superoxide dismutase, catalase and glutathione peroxidase significantly decreased (P<0.01). When mice were treated with morphine combined with exogenous antioxidants, glutathione and ascorbic acid, all the indexes of oxidative damage and the activity of alanine aminotransferase showed no changes as compared to those of control (P>0.05), i.e., both glutathione and ascorbic acid completely abolished the damage of morphine on the hepatocyte. These results implied that morphine caused a seriously oxidative stress in mice livers and hence caused hepatotoxicity, while exogenous antioxidants were able to prevent the oxidative damage of biomolecules and hepatotoxicity caused by morphine. Thus, blocking oxidative damage may be a useful strategy for the development of a new therapy for opiate abuse. [source] Decreased biliary excretion of tributylmethyl ammonium in cholestyramine pretreated rats due to reduced formation of ion-pair complexes with hepatic bile saltsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 9 2007M. K. Choi Abstract The hypothesis that higher molecular weight (MW) quaternary ammoniums (QAs) form lipophilic ion-pair complexes with bile salts in the liver, and are subsequently excreted into bile via a canalicular transporter, P-gp, was re-examined in the present study for its validity. The biliary excretion of tributylmethyl ammonium (TBuMA), a QA with a MW of 200, in bile salt-depleted rats was determined. Depletion was induced by a daily oral administration of a resin, cholestyramine, at a dose of 0.5,g/kg for 2 consecutive weeks, which decreased the concentration of total bile salts in the liver by 38%. When TBuMA was administered intravenously (12,µmol/kg) to these rats, the plasma level, area under the plasma concentration-time curve (AUC), systemic clearance (CL) and volume of distribution (Vss) of the compound remained unchanged, whereas bile flow (23.03 vs 16.94,µl/min, p<0.05) and biliary clearance (CLbile, 12.75 vs 5.34,ml/min/kg, p<0.01) were decreased significantly. These results implied the biliary clearance of TBuMA in rats with bile salt depletion was significantly decreased as a result of decreased ion-pair complexation of TBuMA. The above results are consistent with our hypothesis and the existence of a MW threshold (i.e. 200±50 for rats) for the biliary excretion of QAs. Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||||||||