bluuebunny/crossref_metadata_2025_split huggingface dataset:
The application of perfluorooctanoate to investigate trimerization of the human immunodeficiency virus‐1 gp41 ectodomain by electrophoresis
Authors: Lin Chi‐Hui , Chang Chung‐Chieh , Cheng Shu‐Fang , Chang Ding‐Kwo 
Published: July 2008

AbstractThe transmembrane glycoprotein gp41 of human immunodeficiency virus has been proposed to form trimer‐of‐hairpin during virus‐cell membrane fusion. To investigate its oligomerization propensity under soluble and membrane‐mimic conditions, sodium salt of perfluorooctanoate (PFO) was applied. A recombinant gp41 ectodomain devoid of disulfide linkage was overexpressed in Escherichia coli and characterized by MS and circular dichroism spectropolarimetry in PFO solution in comparison to SDS. The helical content of this ectodomain in PFO is higher than that in SDS. Notably, PFO employed in PAGE clearly conduced to the formation of trimer under the optimized condition as visualized in the gel. In addition, the proteins expressed from the two mutants in the heptad repeat (HR) domains of gp41, I62P, and N126K, were also examined by the PFO‐PAGE analysis for functional ramification of molecular organization. Remarkably, the I62P mutation completely abolished the gp41 trimer formation, whereas the N126K mutation resulted in a more stable trimer. The data suggested that PFO‐PAGE analysis is appropriate for evaluating the effect of mutations on the trimerization of gp41 and other fusion proteins which may be implicated in the alteration of their fusogenicity.
Metabolic fingerprinting of Schistosoma mansoni infection in mice urine with capillary electrophoresis
Authors: García‐Pérez Isabel , Whitfield Philip , Bartlett Ann , Angulo Santiago , Legido‐Quigley Cristina , Hanna‐Brown Melissa , Barbas Coral 
Published: July 2008

AbstractSchistosoma mansoni infection in mice has been fingerprinted using CE to study the capabilities of this technique as a diagnostic tool for this parasitic disease. Two modes of separation were used in generating the electrophoretic data, with each untreated urine sample the following methods were applied: (i) a fused‐silica capillary, operating with an applied potential of 18 kV, in micellar EKC (MEKC) and (ii) a polyacrylamide‐coated capillary, operating with an applied potential of −20 kV under zonal CZE conditions. By combining normal and reverse polarities in the data treatment we have extracted more information from the samples, which is a better approach for CE metabolomics. The traditional problems associated with variability in electrophoretic peak migration times for analytes were countered by using a dynamic programming algorithm for the electropherograms alignment. Principal component analyses of these aligned electropherograms and partial least square discriminant analysis (PLS‐DA) data are shown to provide a valuable means of rapid and sample classification. This approach may become an important tool for the identification of biomarkers, diagnosis and disease surveillance.
Determination of levofloxacin and norfloxacin by capillary electrophoresis with electrochemiluminescence detection and applications in human urine
Authors: Liu Yan‐Ming , Cao Jun‐Tao , Tian Wei , Zheng Yan‐Li 
Published: July 2008

AbstractA novel method for the determination of norfloxacin (NOR) and levofloxacin (LVX) was developed by CE separation and electrochemiluminesence detection (ECL). The methods for capillary conditioning and the effect of solvent type were studied. Parameters affecting the CE and ECL were also investigated. Under the optimum conditions, the two analytes were well separated within 9 min. The LODs (S/N = 3) in standard solution are 4.8×10–7 mol/L for NOR and 6.4×10–7 mol/L for LVX, respectively. The precisions of intraday and interday are less than 4.2 and 8.1%, respectively. The LOQs (S/N = 10) in real human urine samples are 1.2×10–6 mol/L for NOR and 1.4×10–6 mol/L for LVX, respectively. The applicability of the proposed method was illustrated in the determination of NOR and LVX in human urine samples and the monitoring of pharmacokinetics for NOR. The recoveries of NOR and LVX at different levels in human urine samples were between 84.3 and 92.3%.
Competitive immunoassay by capillary electrophoresis with laser‐induced fluorescence for the trace detection of chloramphenicol in animal‐derived foods
Authors: Zhang Can , Wang Shuo , Fang Guozhen , Zhang Yan , Jiang Liqin 
Published: July 2008

AbstractA competitive immunoassay using CE with an LIF detector was developed for the detection of chloramphenicol (CAP). The method was based on the competitive reactions between fluorescently labeled CAP hapten and free CAP, with a limited amount of anti‐CAP antibody. The poly(N‐isopropylacrylamide) (pNIPA) hydrogel was added in the separation buffer as a dynamic modifier to reduce adsorption and enhance reproducibility. The linear range and LOD for CAP were 0.008–5 μg/L and 0.0016 μg/L, respectively. An ELISA using the same immuno‐reagents was also developed for the analysis of CAP, with an LOD of 0.03 μg/L. The sensitivity of this CE immunoassay (CEIA)‐LIF was almost 20 times greater than that of the ELISA. Using CEIA‐LIF, equilibrium was reached in 15 min and the analytical results were obtained within 5 min by CE separation. Sample preparation for CEIA‐LIF was not time‐consuming and the matrix effect was easy to remove. An LOD of 0.1 μg/kg CAP in food matrices was easily achieved. This method is thus proposed as a fast and sensitive means of detecting trace amounts of CAP residues in animal‐derived foods.
Heme oxygenase-1 suppresses hepatitis C virus replication and increases resistance of hepatocytes to oxidant injury
Authors: Zhu Zhaowen , Wilson Anne T. , Mathahs Meleah M. , Wen Feng , Brown Kyle E. , Luxon Bruce A. , Schmidt Warren N. 
Published: July 2008

Abstract

Oxidative injury to hepatocytes occurs as a result of hepatitis C virus (HCV) infection and replication. Modulation of host cell antioxidant enzymes such as heme oxygenase-1 (HO-1) may be useful therapeutically to minimize cellular injury, reduce viral replication, and attenuate liver disease. In this report, we evaluated the effects of HO-1 overexpression on HCV replication and hepatocellular injury. Full-length (FL) (Con1) or nonstructural (NS) replicons (I 389 NS3-3′) were transfected with complete human HO-1 sequences or empty vector for control. Cell lines overexpressing HO-1 (twofold to sixfold above basal values) or empty vector were isolated, and their HCV RNA synthesis, pro-oxidant levels, and resistance to oxidative injury were assessed. HO-1 overexpression decreased HCV RNA replication in both FL and NS replicons without affecting cellular growth or DNA synthesis. The attenuation of HCV replication was significantly reversed in both replicon systems with HO-1 small interfering RNA (siRNA) knockdown. Both FL and NS replicons that overexpress HO-1 showed reduced prooxidant levels at baseline and increased resistance to oxidant-induced cytotoxicity. HO-1 induction with hemin also markedly decreased HCV replication in both parental FL and NS replicon cell lines. Conversely, knockdown of HO-1 messenger RNA (mRNA) by siRNA in parental FL or NS replicons did not significantly affect HCV replication, suggesting that less than basal levels of HO-1 had minimal effect on HCV replication.

Conclusion:

Overexpression or induction of HO-1 results in decreased HCV replication as well as protection from oxidative damage. These findings suggest a potential role for HO-1 in antiviral therapy and therapeutic protection against hepatocellular injury in HCV infection. (Hepatology 2008.)
Rab4 facilitates cyclic adenosine monophosphate–stimulated bile acid uptake and Na+-taurocholate cotransporting polypeptide translocation
Authors: Schonhoff Christopher M. , Thankey Krishna , Webster Cynthia R.L. , Wakabayashi Yoshiyuki , Wolkoff Allan W. , Anwer Sawkat M. 
Published: July 2008

Abstract

Cyclic adenosine monophosphate (cAMP) stimulates hepatic bile acid uptake by translocating sodium-taurocholate (TC) cotransporting polypeptide (Ntcp) from an endosomal compartment to the plasma membrane. Rab4 is associated with early endosomes and involved in vesicular trafficking. This study was designed to determine the role of Rab4 in cAMP-induced TC uptake and Ntcp translocation. HuH-Ntcp cells transiently transfected with empty vector, guanosine triphosphate (GTP) locked dominant active Rab4 (Rab4(GTP)), or guanosine diphosphate (GDP) locked dominant inactive Rab4 (Rab4(GDP)) were used to study the role of Rab4. Neither Rab4(GTP) nor Rab4(GDP) affected either basal TC uptake or plasma membrane Ntcp level. However, cAMP-induced increases in TC uptake and Ntcp translocation were enhanced by Rab4(GTP) and inhibited by Rab4(GDP). In addition, cAMP increased GTP binding to endogenous Rab4 in a time-dependent, but phosphoinositide-3-kinase–independent manner.

Conclusion:

Taken together, these results suggest that cAMP-mediated phosphoinositide-3-kinase–independent activation of Rab4 facilitates Ntcp translocation in HuH-Ntcp cells. (Hepatology 2008.)
Degradation of the bile salt export pump at endoplasmic reticulum in progressive familial intrahepatic cholestasis type II
Authors: Wang Lin , Dong Huiping , Soroka Carol J. , Wei Ning , Boyer James L. , Hochstrasser Mark 
Published: July 2008

Abstract

The bile salt export pump (Bsep) represents the major bile salt transport system at the canalicular membrane of hepatocytes. When examined in model cell lines, genetic mutations in the

BSEP

gene impair its targeting and transport function, contributing to the pathogenesis of progressive familial intrahepatic cholestasis type II (PFIC II). PFIC II mutations are known to lead to a deficiency of BSEP in human hepatocytes, suggesting that PFIC II mutants are unstable and degraded in the cell. To investigate this further, we have characterized the impact of several PFIC II mutations on the processing and stability of rat Bsep. G238V, D482G, G982R, R1153C, and R1286Q all retain Bsep to the endoplasmic reticulum (ER) to different extents. Except for R1153C, the PFIC II mutants are degraded with varying half-lives. G238V and D482G are partially misfolded and can be stabilized by low temperature and glycerol. The proteasome provides the major degradation pathway for the PFIC II mutants, whereas the lysosome also contributes to the degradation of D482G. The PFIC II mutants appear to be more heavily ubiquitinated compared with the wild-type (wt) Bsep, and their ubiquitination is increased by the proteasome inhibitors. Overexpression of several E3 ubiquitin ligases, which are involved in ER-associated degradation (ERAD), lead to the decrease of both mutant and wt Bsep. Gene knockdown studies showed that the ERAD E3s Rma1 and TEB4 contribute to the degradation of G238V, whereas HRD1 contributes to the degradation of a mutant lacking the lumenal glycosylation domain (ΔGly). Furthermore, we present evidence that G982R weakly associates with various components of the ER quality control system. These data together demonstrate that the PFIC II mutants except R1153C and ΔGly are degraded by the ERAD pathway. (Hepatology 2008.)
Hereditary hemochromatosis in the post- HFE era
Authors: Olynyk John K. , Trinder Debbie , Ramm Grant A. , Britton Robert S. , Bacon Bruce R. 
Published: July 2008

Abstract

Following the discovery of the

HFE

gene in 1996 and its linkage to the iron overload disorder hereditary hemochromatosis (HH) there have been profound developments in our understanding of the pathogenesis of the biochemical and clinical manifestations of a number of iron overload disorders. This article provides an update of recent developments and key issues relating to iron homeostasis and inherited disorders of iron overload, with emphasis on

HFE

-related HH, and is based on the content of the American Association for the Study of Liver Diseases Single-Topic Conference entitled “Hemochromatosis: What has Happened After

HFE

?” which was held at the Emory Convention Center in Atlanta, September 7-9, 2007. (Hepatology 2008;48:991–1001.)
Groundwater geochemistry of the Chihuahua City region in the Rio Conchos Basin (northern Mexico) and implications for water resources management
Authors: Mahlknecht Jürgen , Horst Axel , Hernández‐Limón Gabriela , Aravena Ramon 
Published: July 2008

AbstractThe Chihuahua City region, located in the semiarid‐arid northern highlands of Mexico, has experienced intensive groundwater abstraction during the last 40 years to meet water demands in the region. A geochemical survey was carried out to investigate the evolution from baseline to modern conditions of a 130‐km flow path including the El Sauz–Chihuahua–Aldama–San Diego de Alcalá regions. The research approach included the use of major chemical elements, chlorofluorocarbons and environmental isotope (18O, 2H, 13C and 14C) tracers. Stable isotopes indicate that groundwater evolves from the evaporation of local rainfall and surface water. Groundwater located at the lower end of the flow section is up to 6000 years old and older groundwater in the order of 9000 years BP was found in a deep well located in the upper part of the flow system, implying contribution from a neighbour basin. The background groundwater chemistry upstream of Chihuahua City results from feldspar weathering. Beyond Chihuahua City the chemical conditions are strongly modified owing to disposal of sewage from public and industrial water supplies into the Rio Chuviscar, subsequent allocation of this water to agricultural irrigation areas and direct infiltration under the river bed. As a consequence, anions like chloride and sulphate are mainly related to surface sources. Nitrate is controlled in part by sewage from public supply and industry and in part by agricultural practices. Arsenic and fluoride are related to weathering of rock formations of local mineralized ranges and subsequent enrichment of the basin‐fill by magmatic processes. The results of this study have implications for groundwater management in an arid region that depends entirely on groundwater for domestic, industrial and agricultural water consumption. Copyright © 2008 John Wiley & Sons, Ltd.
Calibration of an evapotranspiration model to simulate soil water dynamics in a semiarid rangeland
Authors: Maneta M. P. , Schnabel S. , Wallender W. W. , Panday S. , Jetten V. 
Published: July 2008

AbstractSoil is the largest reservoir of water in a catchment and evapotranspiration is the largest yearly output flux of water from the soil in semiarid environments at the catchment scale. Hydrologic stress is one of the typical characteristics of semiarid environments. The shortage of water affects all the biophysical processes and increases the nonlinearity in the rainfall–runoff relationship. A proper description of semiarid watersheds should include an accurate description of the wetting–drying cycle of the soil, which is critical to properly describe important processes such as the connection between the surface and the soil saturated zone, the production of runoff or the growth of plants. Evapotranspiration is typically modelled in comprehensive distributed hydrologic models (e.g. MIKE‐SHE or MODHMS) using functions that relate evapotranspiration to soil moisture and plant biomass through a set of empirical coefficients, which typically adopt some default values regardless of the conditions of the area where the model is applied. In this work, using a global and a local search algorithm, a three‐dimensional soil water flow model coupled to an evapotranspiration model is calibrated in a soil profile covered with grass in a semiarid environment. Four parameters for the water flow model and three parameters for the evapotranspiration model are calibrated. An existing trend between daily average soil moisture and daily maximum temperature is used as extra information during the calibration process. The results showed that the known relationship between maximum temperature and average soil moisture includes information on the seasonality of the atmospheric demand. Although total evapotranspiration is similar in all calibrations, the trade‐off between evaporation and transpiration is sensitive to this extra information mainly through one model parameter. Further research is necessary to identify the value of the parameter that produces the correct trade‐off. Copyright © 2008 John Wiley & Sons, Ltd.
Snowmelt runoff modelling in an arid mountain watershed, Tarim Basin, China
Authors: Li Xingong , Williams Mark W. 
Published: July 2008

AbstractThe feasibility of simulating daily snowmelt runoff in an arid mountain watershed with limited hydro‐meteorological measurements was explored with an enhanced temperature‐index snowmelt runoff model (SRM) in which the degree‐day factor (DDF) is varied on the basis of shortwave solar radiation and snow albedo. The model satisfactorily simulated snowmelt runoff with a model efficiency of 0·64 for the calibration year and efficiency values of 0·78 and 0·51 for two validation years. Analysis indicated that the model was sensitive to lapse rate and snow albedo parameterization. The distinct seasonal variation of lapse rate played a key role for successful simulation. Snow albedo parameterization, which directly scaled snow cover percentage into snow albedo, worked quite well for the watershed although further validation is needed. Eight‐day snow cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to feed the model. A frequency filter, which filtered out the clouds and large fluctuation of snow cover from the MODIS snow cover data, also improved model performance. The model, however, did not simulate peak stream flows well as most of the model runs underestimated them. Copyright © 2008 John Wiley & Sons, Ltd.
Variation in runoff with age of Chinese fir plantations in Central South China
Authors: Tian Dalun , Yan Wende , Chen Xiaoyong , Deng Xiangwen , Peng Yuanying , Kang Wenxing , Peng Changhui 
Published: July 2008

AbstractTo determine the influence of forest structures on runoff characteristics, the hydrological effects of Chinese fir plantations were studied by analysing runoff patterns at different growth and development stages (stand age classes I to V) from 1984 to 2004 at the Huitong Ecosystem Research Station, Central South University of Forestry and Technology, Hunan Province, Central South China. Results for two small experimental Chinese fir watersheds showed different peak values for surface runoff amount and coefficients at different ages, with lowest values in age classes I and V and highest values in age classes II and III. However, both underground and total runoff coefficients decreased with increasing age class. Total runoff coefficient was about twice as high in age class I (30·8%) as that in age class V (15·8%). Higher underground and total runoff coefficients were found in young forests. This was mainly attributed to soil disturbance due to human management practices such as site ploughing. Results indicate that Chinese fir plantations play a significant role in regulating water distribution in the watershed. Useful information is provided on the effects of forest management practices on hydrological processes in forest plantations. Copyright © 2008 John Wiley & Sons, Ltd.
Nuclear karyopherin α2 expression predicts poor survival in patients with advanced breast cancer irrespective of treatment intensity
Authors: Gluz Oleg , Wild Peter , Meiler Robert , Diallo‐Danebrock Raihana , Ting Evelyn , Mohrmann Svjetlana , Schuett Gerhart , Dahl Edgar , Fuchs Thomas , Herr Alexander , Gaumann Andreas , Frick Markus , Poremba Christopher , Nitz Ulrike Anneliese , Hartmann Arndt 
Published: July 2008

AbstractIntensive lymph node involvement indicates poor prognosis in breast cancer patients. The significance of other molecular prognostic factors in this subgroup is unclear. Karyopherin α2 (KPNA2) has been reported as an important factor of tumorgenesis and progression of breast cancer. The aim of present study was to evaluate the impact of KPNA2 expression on prognosis of patients with high risk breast cancer (HRBC) and response intensive chemotherapy within the randomized WSG‐AM‐01 trial. KPNA2 nuclear expression (>10% vs. <10% of nuclei) was measured by immunohistochemistry on tissue arrays of 191 patients randomized to tandem high dose vs. conventional dose‐dense chemotherapy in HRBC with >9 positive lymph nodes and correlated with clinical outcome (median follow‐up of 63.3 months) by Kaplan–Meier and multivariate Cox hazard model analysis, including, molecular subtypes determined by k‐clustering (k = 5). KPNA2 overexpression (n = 74, 39%) significantly correlated with shorter event‐free and overall survival (OS) in both therapy arms by univariate analysis. Multivariate analysis showed that the overexpression of KPNA2 was an independent prognostic factor of decreased OS HR = 1.86 [95% CI: 1.07–3.23, p = 0.03]. This predictive value was independent of basal‐like/Her‐2/neu subtypes, significantly associated with KPNA2 and was addressed particularly to G2 tumors. Our data suggest the use of KPNA2 nuclear expression as novel prognostic marker in node‐positive patients, especially in determination of G2 tumors in 2 subgroups of different prognosis. KPNA2 expression may be also considered as a marker for global chemoresistance, which can not be overcome by conventional dose‐modification of chemotherapy in advanced breast cancer. © 2008 Wiley‐Liss, Inc.
Sulforaphane inhibited expression of hypoxia‐inducible factor‐1α in human tongue squamous cancer cells and prostate cancer cells
Authors: Yao Hua , Wang Huiming , Zhang Zhuo , Jiang Bing‐Hua , Luo Jia , Shi Xianglin 
Published: July 2008

AbstractPrevious studies show that a number of natural compounds from our diet have anticancer effects. Sulforaphane is the most characterized isothiocyanates (ITCs), which are identified in cruciferous vegetables. Sulforaphane is viewed as a conceptually promising agent in cancer prevention. Because of its ability to induce cancer cell apoptosis, it inhibits progression of benign tumors to malignant tumors and interrupts metastasis. However, the effect of sulforaphane on tongue cancer cell proliferation has not yet been reported, and the mechanisms that sulforaphane inhibits cancer development are still unclear. Hypoxia‐inducible factor 1 (HIF‐1) expression is associated with tumorigenesis and angiogenesis. It regulates the expression of many genes including vascular endothelial growth factor (VEGF), inducible nitric oxide synthase, and lactate dehydrogenase A. In our study, we investigated the effects of sulforaphane on expression of hypoxia‐inducible factor‐1α (HIF‐1α), which was overexpressed in many human malignant tumors, human tongue squamous cell carcinoma and prostate cancer DU145 cells. Sulforaphane inhibited hypoxia induced expression of HIF‐1αviainhibiting synthesis of HIF‐1α. Sulforaphane was also found to inhibit hypoxia induced HIF‐1α expression through activating JNK and ERK signaling pathways, but not AKT pathway. Inhibition of HIF‐1α by sulforaphane resulted in decreasing expression of VEGF. Taken together, these results suggest that sulforaphane is an effective chemopreventive compound against tongue cancers and prostate cell angiogenesisin vitro, and that the HIF‐1α target provides a new sight into the mechanisms of sulforaphane's inhibition against tumor cell proliferation. © 2008 Wiley‐Liss, Inc.