bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular basis of vanadium‐mediated inhibition of hepatocellular preneoplasia during experimental hepatocarcinogenesis in rats
Authors: Chakraborty Tridib , Swamy A.H.M. Viswanatha , Chatterjee Amrita , Rana Basabi , Shyamsundar A. , Chatterjee Malay 
Published: January 2007

AbstractCarcinogen‐induced early DNA lesions and metallothionein (MT) over‐expression have been implicated in cell proliferation and thereby subsequent expression of premalignant phenotype of the cell. We have therefore investigated the chemopreventive potential of vanadium in a multi‐biomarker approach, viz. 8‐hydroxy‐2′‐deoxyguanosines (8‐OHdGs), DNA single‐strand breaks (SSBs), DNA‐protein crosslinks (DPCs), chromosomal aberrations (CAs), in situ MT expression, and cell proliferation in rat liver preneoplasia. Hepatocarcinogenesis was induced in male Sprague–Dawley rats with a single, necrogenic, intraperitoneal (i.p.) injection of diethylnitrosamine (DEN) (200 mg/Kg body weight) at week 4 of the experimental protocol followed by promotion with phenobarbital (PB) (0.05% in basal diet), on and from week 8 and continued till 32 weeks in a long‐term regimen. There was a significant and steady elevation of modified DNA bases 8‐OHdGs (P < 0.0001; 90.69%) along with substantial increments of the extent of SSBs (P < 0.001) and CAs (P < 0.001) following DEN exposure. Supplementation of vanadium at a dose of 0.5 ppm abated the formations of 8‐OHdGs (80.63%; P < 0.0001), SS‐DNAs (P < 0.001) and SSBs/DNA unit (P < 0.01; 56.39%), DPCs (59.26%; P < 0.0001) and CAs (71.52%; P < 0.001) in preneoplastic rat liver studied at various time points. Low dose of vanadium treatment further reduced liver‐MT immunoreactivity (P < 0.05) and BrdU‐labeling index (P < 0.02) and a significant positive correlation (r = 0.92; r2 = 0.85; P = 0.0001) was noted between them. Continuous vanadium administration also decreased nodular incidence (66.67%) and nodule multiplicity (62.12%; P < 0.001) along with substantial improvement in the altered hepatocellular phenotype when compared to DEN + PB treatment alone. The study indicates that vanadium‐mediated suppression of cell proliferation and resulting premalignant expression might be due to the observed reductions in hepatic 8‐OHdGs, SSBs, DPCs, CAs, and MT immunoreactivity. Vanadium is chemopreventive for DEN‐induced hepatocellular preneoplasia in rats. J. Cell. Biochem. 101: 244–258, 2007. © 2007 Wiley‐Liss, Inc.
Pay high in good times, pay low in bad times
Authors: Schröder Michael , Heinemann Friedrich , Kruse Susanne , Meitner Matthias 
Published: January 2007

AbstractThe paper examines the applicability of GDP‐linked bonds for the financing of developing countries. These bonds are characterised by tying the coupon and/or redemption payments to the GDP of the issuing country. Along with an analysis of their pricing behaviour and of their behaviour in a portfolio context, the study also encompasses a survey amongst financial experts in order to assess the prospects of success of this type of bond. Finally, the usefulness of a partial public guarantee of payments is examined. The paper provides evidence under which circumstances, for which investors and for which countries, GDP‐linked bonds might be an appropriate investment vehicle. Copyright © 2007 John Wiley & Sons, Ltd.
Chemoenzymatic n.c.a synthesis of the coenzyme UDP‐2‐deoxy‐2‐[18F]fluoro‐α‐D‐glucopyranose as substrate of glycosyltransferases
Authors: Prante Olaf , Hamacher Kurt , Coenen Heinz H. 
Published: January 2007

AbstractThe development of 18F‐labelling methods adopted to proteins and bioactive peptides is of great interest in radiopharmaceutical sciences. In order to provide 18F‐labelled sugars as a polar prosthetic group for an enzymatic 18F‐labelling procedure, an appropriate nucleotide activated sugar is needed. Here, we present the radiosynthesis of n.c.a. UDP‐2‐deoxy‐2‐[18F]fluoro‐α‐D‐glucopyranose (UDP‐[18F]FDG) as a substrate for glycosyltransferases. The MacDonald synthesis of [18F]FDG‐1‐phosphate was successfully combined with an enzymatic activation to obtain UDP‐[18F]FDG directly in an aqueous medium located in the void volume of a solid phase cartridge. The radiochemical yield of UDP‐[18F]FDG was 20% (based on [18F]fluoride) after a total synthesis time of 110 min. Thus, an intermediate was provided for the enzymatic transfer of [18F]FDG using UDP‐[18F]FDG as glycosyl donor making use of a suitable glycosyltransferase. This would represent a highly selective and mild 18F‐labelling method for glycosylated biomolecules. Copyright © 2007 John Wiley & Sons, Ltd.
Liquid chromatography‐mass spectrometry method for quantification of caspofungin in clinical plasma samples
Authors: Rochat Bertrand , Bolay Saskia , Pascual Andres , Calandra Thierry , Marchetti Oscar 
Published: January 2007

AbstractCaspofungin [(CASPO) MK‐0991] is the first broad‐spectrum anti‐fungal agent of the echinocandin class approved for clinical use. Measurement of CASPO levels in blood might help monitor therapy in patients who are critically ill, in particular, if high‐dose regimens or combinations of CASPO with other anti‐fungals are used. The objective of this study was to develop a fast method for the measurement of CASPO levels in clinical blood samples using liquid chromatography coupled to a triple‐quadrupole mass spectrometer. Stock solutions were prepared in plasma to avoid CASPO adsorption to glass and plastic surfaces during processing. CASPO and the internal standard (IS) were extracted from 100 µl of plasma using acetonitrile protein precipitation. The supernatant was diluted and directly injected into an analytical column (C8; 2.1 × 30 mm). The total run time was 15 min. CASPO was ionized by electrospray in the positive mode. CASPO and IS [M + 2H]2+ parent ions (m/z 547.3 and 547.8, respectively) and specific product ions (m/z 137.1 and 62.2, respectively) were used for the ion transitions. No carry over or cross‐talk was observed on the column. The mean method recovery was 90 ± 3%. Neither blood from different individuals (n = 6) nor the presence of concomitant drugs (n = 33) in plasma samples interfered with CASPO quantification. Quantification over time of the CASPO levels in plasma and whole blood was investigated at different pre‐analysis storage conditions. The calibration curve included the clinically relevant CASPO concentration range from 0.04 to 20 µg/ml. Mean intra‐ and inter‐day accuracy was 96.1 ± 2.2% and 102.5 ± 2.4%, respectively. Mean intra‐ and inter‐day precision was 7.9 ± 3.2% and 6.3 ± 1.8%, respectively. This simple and robust liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method may easily be implemented for monitoring CASPO therapy. Copyright © 2007 John Wiley & Sons, Ltd.
Apoptotic and behavioral sequelae of mild brain trauma in mice
Authors: Tweedie David , Milman Anat , Holloway Harold W. , Li Yazhou , Harvey Brandon K. , Shen Hui , Pistell Paul J. , Lahiri Debomoy K. , Hoffer Barry J. , Wang Yun , Pick Chaim G. , Greig Nigel H. 
Published: January 2007

AbstractMild traumatic brain injury (mTBI) is a not uncommon event in adolescents and young adults. Although it does not result in clear morphological brain defects, it is associated with long‐term cognitive, emotional, and behavioral problems. Herein, we characterized the biochemical and behavioral changes associated with experimental mTBI in mice that may act as either targets or surrogate markers for interventional therapy. Specifically, mTBI was induced by 30‐g and 50‐g weight drop, and at 8 and 72 hr thereafter markers of cellular apoptosis—caspase‐3, Bax, apoptosis‐inducing factor (AIF), and cytochrome‐c (Cyt‐c)—were quantified by Western blot analysis in hippocampus ipsilateral to the impact. Levels of amyloid‐β precursor protein (APP) were also measured, and specific behavioral tests—passive avoidance, open field, and forced swimming (Porsolt) paradigms—were undertaken to assess learning, emotionality, and emotional memory. In the absence of hemorrhage or infarcts, as assessed by triphenyltetrazolium chloride staining, procaspase‐3 and Bax levels were markedly altered following mTBI at both times. No cleaved caspase‐3 was detected, and levels of AIF and Cyt‐c, but not APP, were significantly changed at 72 hr. Mice subjected to mTBI were indistinguishable from controls by neurological examination at 1 and 24 hr, and by passive avoidance/open field at 72 hr, but could be differentiated in the forced swimming paradigm. In general, this model mimics the diffuse effects of mTBI on brain function associated with the human condition and highlights specific apoptotic proteins and a behavioral paradigm as potential markers for prospective interventional strategies. © 2007 Wiley‐Liss, Inc.
Mitochondria in cybrids containing mtDNA from persons with mitochondriopathies
Authors: Swerdlow Russell H. 
Published: January 2007

AbstractThe cytoplasmic hybrid (cybrid) technique allows investigators to express selected mitochondrial DNA (mtDNA) sequences against fixed nuclear DNA (nDNA) backgrounds. Cybrids have been used to study the effects of known mtDNA mutations on mitochondrial biochemistry, mtDNA‐nDNA inter‐species compatibility, and mtDNA integrity in persons without mtDNA mutations defined previously. This review discusses events leading up to creation of the cybrid technique, as well as data obtained via application of the cybrid strategies listed above. Although interpreting cybrid data requires awareness of technique limitations, valuable insights into mtDNA genotype‐functional phenotype relationships are suggested. © 2007 Wiley‐Liss, Inc.
Excitotoxic motoneuron disease in chick embryo evolves with autophagic neurodegeneration and deregulation of neuromuscular innervation
Authors: Calderó Jordi , Tarabal Olga , Casanovas Anna , Ciutat Dolors , Casas Celia , Lladó Jerònia , Esquerda Josep E. 
Published: January 2007

AbstractIn the chick embryo, in ovo application of NMDA from embryonic day (E) 5 to E9 results in selective damage to spinal cord motoneurons (MNs) that undergo a long‐lasting degenerative process without immediate cell death. This contrasts with a single application of NMDA on E8, or later, which induces massive necrosis of the whole spinal cord. Chronic MN degeneration after NMDA implies transient incompetence to develop programmed cell death, altered protein processing within secretory pathways, and late activation of autophagy. Chronic NMDA treatment also results in an enlargement of thapsigargin‐sensitive Ca2+ stores. In particular MN pools, such as sartorius‐innervating MNs, the neuropeptide CGRP is accumulated in somas, peripheral axons and neuromuscular junctions after chronic NMDA treatment, but not in embryos paralyzed by chronic administration of curare. Intramuscular axonal branching is also altered severely after NMDA: it usually increases, but in some cases a marked reduction can also be observed. Moreover, innervated muscle postsynaptic sites increase by NMDA, but to a lesser extent than by curare. Because some of these results show interesting homologies with MN pathology in human sporadic ALS, the model presented here provides a valuable tool for advancing in the understanding of some cellular and molecular processes particularly involved in this disease. © 2007 Wiley‐Liss, Inc.
Objective air temperature mapping for the Iberian Peninsula using spatial interpolation and GIS
Authors: Ninyerola Miquel , Pons Xavier , Roure Joan M. 
Published: January 2007

AbstractThis study presents an objective mapping of monthly mean air temperature over the Iberian Peninsula using the spatial interpolation of climatological data. The research focuses on an interpolation method (multiple regression with residual correction) that combines statistical global analysis with a local interpolation (splines and inverse distance weighting). Geographical information (the independent variables) is used to predict air temperature (the dependent variable) through the regression relationship and to test several approaches. A comprehensive GIS implementation makes it possible to address many cartographic issues and to produce mean minimum, mean and mean maximum air temperature surfaces for the entire Iberian Peninsula. The spatial resolution of the maps is 200 m and their temporal resolution is monthly and annual. An associated error level obtained through validation tests with independent data is computed for each map. These validation tests show that the best results have an average R2 (mean of all months) of 0.91 (mean temperature), 0.87 (mean maximum temperature) and 0.83 (mean minimum temperature). When the objective is to map a large area, best results are obtained when the model uses all stations of the Iberian Peninsula together (general peninsular model) and not when using different local subsets (hydrographical basins regional models). However, when the objective is mapping a regional area, basin models produce better outcomes than the general model being applied to these regional areas. Copyright © 2007 Royal Meteorological Society
Synchronization between the North Sea–Caspian pattern (NCP) and surface air temperatures in NCEP
Authors: Tatli Hasan 
Published: January 2007

AbstractIn this study, synchronous linkages of the North Sea–Caspian pattern (NCP), associated with large‐scale surface air temperature series selected from National Centers for Environmental Prediction–National Center of Atmospheric Research reanalysis (NCEP‐NCAR) for the region over 50°W–120°E and 0–80°N are investigated via teleconnection patterns based on phase synchronization. Phase synchronization is the process by which two or more cyclic systems (or subsystems) tend to oscillate with a repeating sequence of relative phase angles. Phase synchronization is usually applied to two waveforms of the same frequency with identical phase angles in each cycle. However, the notion of phase synchronization has been introduced as an extension of classical Huygens' synchronization in the case of interacting chaotic systems if there is an integer relationship of frequency, such that the cyclic systems share a repeating sequence of phase angles over consecutive cycles. The results of the phase synchronization method are compared with those of the classical cross‐correlation method in cases in which cross‐correlation method shows linear spatial cross‐dependency, but the phase synchronization yields nonlinear spatial phase dependency. In the analyses, teleconnection patterns derived from phase synchronization are first calculated for raw and de‐seasoned data (by removing periodic components in the surface air temperature series) in year‐month scale and then for the data in seasonal‐scale (namely, winter, spring, summer and autumn). Teleconnection patterns calculated by phase synchronization improve the experiential intra‐phase relationships between the NCP Index (NCPI) and large‐scale surface air temperature series, and ensures that the major modes of mid and high Northern Hemisphere variability in climate are characterized. Statistically significant phase synchronization patterns related to geopotential dipole heights of the NCPI extending over Greenland, the Balkans, Caspian Sea basin, eastern Mediterranean, Turkey and the Middle East, and further phase synchronization patterns over the circumpolar mode, which are utilized by phase interaction of Arctic oscillation (AO) with NCP, are obtained. In addition, significant phase synchronization patterns are also obtained over Tibetan plateau–Mongolia (Gobi Desert) interacting with the Siberian high, Asiatic monsoon and the intertropical convergence zone. Copyright © 2007 Royal Meteorological Society
Comprehensive analysis of the climate variability in the eastern Mediterranean. Part I: map‐pattern classification
Authors: Kostopoulou E. , Jones P. D. 
Published: January 2007

AbstractThis paper provides an extended study of the dominant daily circulation patterns governing the climate variability in the eastern Mediterranean. The methodology adopted to determine the circulation patterns is based on combined analysis of the spatial and temporal variation of rotated principal components of sea‐level pressure. A catalogue of characteristic seasonal composites is presented and discussed. It is found that, during winter and spring, large scale features situated in northern Europe affect the atmospheric circulation over the domain of study, whereas the Atlantic (Azores) anticyclone and the Asian Thermal Low define most of the observed circulation types in summer. In autumn, the area exhibits a rapid transition from the warm to cold season showing climatic features from both extreme seasons. Similarities between winter and spring/autumn patterns are detected and correlation analyses are employed between their spatial patterns to reveal that similar circulation patterns occur amongst the three seasons, which usually appear more pronounced during winter. Frequencies and trends of the proposed circulation types are examined for each season. A linear trend analysis for the overall period (1958–2000) exhibits a significant increase in the anticyclonic types particularly in winter. With respect to the cyclonic types, statistically significant negative trends have been found in all seasons especially for types associated with depressional activity in central the Mediterranean. Copyright © 2007 Royal Meteorological Society
Analysis of soil organic matter biomarkers by sequential chemical degradation and gas chromatography – mass spectrometry
Authors: Otto Angelika , Simpson Myrna J. 
Published: January 2007

AbstractLow molecular weight (LMW) biomarkers can be used to trace the source and stage of soil organic matter. However, methods that selectively isolate these groups of compounds are underdeveloped. In this study, we isolate biomarkers by a successive series of extraction and chemical degradation procedures involving solvent extraction (TSE), base (BHY) and acid hydrolysis (AHY), and CuO oxidation (CUO). GC‐MS was used to analyze these fractions and the extraction methods were verified by solid‐state 13C NMR spectroscopy. The GC‐MS response was high for the BHY products (96%), intermediate for the TSE (30%) and CUO (19%), but very low for the AHY fraction (5%) indicating that the fractions contain polar or high molecular weight compounds. Aliphatic lipids (62%), phenols and benzyls (17%) were the predominant classes, accompanied by minor abundances of mono‐ and disaccharides, LMW acids, terpenoids, steroids, amino acids, and amino sugars. The TSE and BHY fractions contained mainly aliphatic lipids derived from plant waxes, cutin, and suberin. Lignin‐derived phenols are the major products in the CUO fraction, and amino compounds and carbohydrates of various sources were identified in the AHY products. The sequential degradation method is useful for the isolation and identification of apolar, LMW biomarkers in soil.
Quantification of testosterone and epitestosterone in human urine samples by stir bar sorptive extraction – thermal desorption – gas chromatography/mass spectrometry: Application to HIV‐positive urine samples
Authors: Stopforth Adriana , Grobbelaar Cornelis J. , Crouch Andrew M. , Sandra Pat 
Published: January 2007

AbstractA simple method is described for the measurement of testosterone (T) and epitestosterone (ET) in human urine samples. The deconjugated steroids were extracted directly from the samples by stir bar sorptive extraction (SBSE) and derivatized in situ on the stir bar by headspace acylation prior to thermal desorption and GC/MS. Extraction and derivatization parameters, namely salt addition, temperature, and time, were optimized to improve the recovery of T and ET by SBSE. The limits of quantification (S/N 10) were 0.9 ng/mL for T and 2.8 ng/mL for ET. Quantification of the steroids in urine samples was performed using standard addition to avoid the influence of matrix effects. The method was applied for the measurement of urinary T and ET in a group of healthy volunteers and HIV+ patients. Decreased levels of T were detected in the HIV+ group, whereas the excretion of ET was comparable for the two groups. Further clinical research is required to elucidate the biomarker significance of the T/ET ratio in HIV infection.
Identification of neuropeptides in rat brain rhinencephalon
Authors: Mihailova Albena , Karaszewski Bartosz , Hauser Roman , Lundanes Elsa , Greibrokk Tyge 
Published: January 2007

AbstractA capillary two‐dimensional liquid chromatography method coupled with ion trap mass spectrometry has been used for separation and identification of neuropeptides in rat rhinencephalon. Animals of three different age groups were exposed to slow and quick CO2 influx. The neuropeptides were extracted by solid phase extraction and the purified extracts were analysed by 2‐D HPLC. The compounds were fractionated (strong cation exchange column), trapped and separated, and MS/MS fragment mass spectra were used for identification. About thirty peptide compounds were identified. A significant difference between concentration levels of “stressed” (quick CO2 influx) and “non‐stressed” (slow CO2 influx) rats was found for 25 of the identified peptides.
Solution Behavior of Temperature‐Responsive Molecular Brushes Prepared by ATRP
Authors: Pietrasik Joanna , Sumerlin Brent S. , Lee Robert Y. , Matyjaszewski Krzysztof 
Published: January 2007

AbstractMolecular brushes, with side chains consisting of two copolymers: 2‐(dimethylamino)ethyl methacrylate with methyl methacrylate, and N,N‐dimethylacrylamide with butyl acrylate were prepared by grafting‐from via atom transfer radical polymerization (ATRP). Poly(2‐(2‐bromoisobutyryloxy)ethyl methacrylate) and poly(2‐(2‐bromopropionyloxy)ethyl methacrylate) were used as macroinitiators. Dynamic light scattering (DLS) studies were performed for aqueous solutions of molecular brushes below and above the lower critical solution temperature (LCST), and an unusual concentration‐dependent LCST was observed. Due to the compact structure of molecular brushes, intramolecular collapse can occur when the average distance between molecules is much larger than the hydrodynamic dimensions of the individual macromolecules. However, if the concentration of the solution of molecular brushes is increased to the level in which the separation distance is comparable with the brush hydrodynamic dimensions, intermolecular aggregation occurs, as typically observed for solutions of linear polymers.magnified image
Improvement of the Mechanical Properties and Creep Resistance of SBS Block Copolymers by Nanoclay Fillers
Authors: Lietz Siljana , Yang Jing‐Lei , Bosch Eva , Sandler Jan K. W. , Zhang Zhong , Altstädt Volker 
Published: January 2007

AbstractSBS nanocomposites based on a SBS triblock copolymer containing different weight fractions of a commercial Cloisite 20A organoclay were prepared by melt‐processing. Extensive electron microscopy as well as WAXS and static tensile and tensile creep tests were used to evaluate the resulting morphological and mechanical properties of the nanocomposites. The nanocomposite morphology is characterized by a combination of intercalated and partly exfoliated clay platelets with occasional clay aggregates present at higher clay contents; nanocomposite features that are reflected by the results of both the static tensile as well as the tensile creep tests at room temperature. For this particular thermoplastic elastomer nanocomposite system, well dispersed nanoclays lead to an enhanced stiffness and ductility; effects that induce promising improvements in nanocomposite creep performance.magnified image