bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perspectives on the use of electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for short tandem repeat genotyping in the post‐genome era
Authors: Null Allison P. , Muddiman David C. 
Published: August 2002

AbstractThe recent completion of the first rough draft of the human genome has provided fundamental information regarding our genetic make‐up; however, the post‐genome era will certainly require a host of new technologies to address complex biological questions. In particular, a rapid and accurate approach to characterize genetic markers, including short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) is demanded. STRs are the most informative of the two polymorphisms owing to their remarkable variability and even dispersity throughout eukaryotic genomes. Mass spectrometry is rapidly becoming a significant method in DNA analysis and has high probability of revolutionizing the way in which scientists probe the human genome. It is our responsibility as biomolecular mass spectrometrists to understand the issues in genetic analysis and the capabilities of mass spectrometry so that we may fulfill our role in developing a rapid, reliable technology to answer specific biological questions. This perspective is intended to familiarize the mass spectrometry community with modern genomics and to report on the current state of mass spectrometry, specifically electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry, for characterization of STRs. Copyright © 2001 John Wiley & Sons, Ltd.
Simultaneous determination of etoposide and its catechol metabolite in the plasma of pediatric patients by liquid chromatography/tandem mass spectrometry
Authors: Pang Shaokun , Zheng Naiyu , Felix Carolyn A. , Scavuzzo Jennifer , Boston Ray , Blair Ian A. 
Published: August 2002

AbstractThe anticancer drug etoposide is associated with leukemias with MLL gene translocations and other translocations as a treatment complication. The genotype of cytochrome P450 3A4 (CYP3A4), which converts etoposide to its catechol metabolite, influences the risk. In order to perform pharmacokinetic studies aimed at further elucidation of the translocation mechanism, we have developed and validated a liquid chromatography/electrospray/tandem mass spectrometry assay for the simultaneous analysis of etoposide and its catechol metabolite in human plasma. The etoposide analog teniposide was used as the internal standard. Liquid chromatography was performed on a YMC ODS‐AQ column. Simultaneous determination of etoposide and its catechol metabolite was achieved using a small volume of plasma, so that the method is suitable for pediatric patients. The limits of detection were 200 ng ml−1 etoposide and 10 ng ml−1 catechol metabolite in human plasma and 25 ng ml−1 etoposide and 2.5 ng ml−1 catechol metabolite in protein‐free plasma, respectively. Acceptable precision and accuracy were obtained for concentrations in the calibration curve ranges 0.2–100 µg ml−1 etoposide and 10–5000 ng ml−1 catechol metabolite in human plasma. Acceptable precision and accuracy for protein‐free human plasma in the range 25–15 000 ng ml−1 etoposide and 2.5–1500 ng ml−1 etoposide catechol were also achieved. This method was selective and sensitive enough for the simultaneous quantitation of etoposide and its catechol as a total and protein‐free fraction in small plasma volumes from pediatric cancer patients receiving etoposide chemotherapy. A pharmacokinetic model has been developed for future studies in large populations. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of anhydroecgonine methyl ester N‐oxide, a new metabolite of anhydroecgonine methyl ester, using electrospray mass spectrometry
Authors: Fandiño Anabel S. , Karas Michael , Toennes Stefan W. , Kauert Gerold 
Published: August 2002

AbstractCocaine is transformed into hepatotoxic metabolites through oxidative pathways. For anhydroecgonine methyl ester (AEME), the main constituent in crack smoke, the oxidative metabolism has not been studied. Therefore, incubation of AEME with rat liver microsomes was performed and a metabolite of AEME, anhydroecgonine methyl ester N‐oxide (AEMENO), was identified. The chemical structure of this new metabolite was confirmed by synthesis and by comparative interpretation of electrospray multiple‐stage mass spectra, which were obtained in the positive ion mode. This metabolite was also detected in whole blood, serum and urine samples from crack users. The application of liquid chromatography/electrospray mass spectrometry or nanoelectrospray mass spectrometry was necessary because AEMENO is susceptible to thermal degradation during gas chromatographic/mass spectrometric analysis. This study demonstrated that AEMENO is produced by rat hepatic microsomal metabolism in vitro and is present in body fluids from crack users. Copyright © 2002 John Wiley & Sons, Ltd.
Prevalence and genotypic distribution of TT virus in Athens, Greece*
Authors: Katsoulidou Antigoni , Paraskevis Dimitrios , Anastassopoulou Cleo G. , Chryssou Stella‐Eugenie , Sypsa Vassiliki , Boletis John , Malliori Meni , Karafoulidou Anastasia , Tassopoulos Nicholas C. , Hatzakis Angelos 
Published: August 2002

AbstractThe prevalence of TT virus (TTV) infection in various population groups from Athens, Greece, was assessed by the polymerase chain reaction (PCR) using two primer sets from distinct regions of the genome: the conventional set derived from the open reading frame‐1 (ORF‐1) and the new, highly sensitive set targeting the region that includes the TATA signal localized upstream of ORF‐2. Based on both primer sets, TTV DNA was detected in 42/50 (84.0%) healthy individuals, 42/50 (84.0%) chronic hepatitis C patients, 31/39 (79.5%) acute non‐A–E hepatitis patients (group I), 14/16 (87.5%) renal failure patients with acute non‐A–E hepatitis (group II), 47/50 (94.0%) intravenous drug users (IVDU), 36/50 (72.0%) hemophiliacs, and 21/31 (67.7%) hemodialysis patients. The presence of TTV was not associated with any particular risk group, and no differences were observed in relation to demographic, biochemical and virological characteristics between TTV DNA‐positive and ‐negative patients. TTV did not seem to have a profound effect on the course of chronic C or acute non‐A–E hepatitis either. Phylogenetic analysis revealed that TTV strains circulating in the greater metropolitan area of Athens belong not only to the G1 and G2 genotypes that are encountered worldwide, but also to G3 and to G5 that are found mainly in Europe and Asia, respectively. Further studies will shed light on the role of this highly prevalent virus. J. Med. Virol. 65:423–429, 2001. © 2001 Wiley‐Liss, Inc.
In vitro regulated expression of tyrosine hydroxylase in ventral midbrain neurons from Nurr1‐null mouse pups
Authors: Eells Jeffrey B. , Rives Julia E. , Yeung Sin Kei , Nikodem Vera M. 
Published: August 2002

AbstractThe transcription factor Nurr1, an orphan member of the steroid‐thyroid hormone nuclear receptor superfamily, is essential for the proper terminal differentiation of ventral midbrain dopaminergic neurons. Disruption of the Nurr1 gene in mice by homologous recombination abolishes synthesis of dopamine (DA) and expression of DA biosynthetic enzymes, including tyrosine hydroxylase (TH), in the ventral midbrain without affecting the synthesis of DA in other areas of the brain. At birth, however, dopaminergic neuron precursors in Nurr1 null (−/−) pups remain as shown by continued expression of residual, untranslated Nurr1 mRNA not altered by homologous recombination. Since Nurr1 disruption is lethal shortly after birth, to further investigate the developmental properties of these neurons, dissociated ventral midbrain neurons from newborn pups were grown for 5 days on an astrocyte feeder layer, subjected to various treatments and then evaluated for expression of TH by fluorescent immunocytochemistry. Initially, a small percentage of neurons (0.26% ± 0.07%) from the ventral midbrain of Nurr1 −/− pups were TH‐immunoreactive (TH‐IR). No change in TH expression was observed in the presence of glial cell line‐derived neurotrophic factor (GDNF), brain‐derived neurotrophic factor (BDNF), or DA alone or in combination. Treatment with forskolin (Fsk), however, significantly increased the percentage of TH‐IR neurons (1.36% ± 0.15%). Combination of Fsk, BNDF, and DA further increased the percentage of TH‐IR neurons (2.58% ± 0.50%). Therefore, these data suggest that dopaminergic neuron precursors, which develop in vivo without Nurr1, remain in an undifferentiated condition that is permissive to the induction of TH in vitro. J. Neurosci. Res. 64:322–330, 2001. Published 2001 Wiley‐Liss, Inc.
Inhibitory effect of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin on cAMP‐induced differentiation of rat C6 glial cell line
Authors: Takanaga Hiromi , Kunimoto Manabu , Adachi Tatsumi , Tohyama Chiharu , Yasunobu Aoki  
Published: August 2002

AbstractDioxin is suspected to cause adverse effects on the development of the central nervous system (CNS). To investigate the neurotoxic effects of dioxin on the differentiation of astrocytes, rat C6 glial cell line was used as a model, because these cells are induced to express astrocyte markers and to change the cell morphology toward an astrocytic phenotype by increasing intracellular cAMP levels. When C6 cells were simultaneously exposed to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) and N6,O2′‐dibutylyl cAMP (dbcAMP), the expression of cytochrome P‐450 1A1 (CYP1A1) was dramatically increased, and the expression of aryl hydrocarbon receptor (AhR) was moderately decreased in a dose‐dependent manner. In addition, extension of astrocytic processes was inhibited by 1 nM TCDD that did not reduce cell viability. TCDD also inhibited the induction of glial fibrillary acidic protein (GFAP) expression in a dose‐dependent manner, until the end of a 72‐hr exposure period. This inhibition was restored by the addition of an antagonist of AhR, α‐naphthoflavone. These results indicate that TCDD inhibits astrocytic differentiation of C6 cells, which may be mediated by an AhR‐dependent pathway. J. Neurosci. Res. 64:402–409, 2001. © 2001 Wiley‐Liss, Inc.
Neurofilament cytoskeleton disruption does not modify accumulation of trophic factor mRNA
Authors: Robert Patrick , Peterson Alan C. , Eyer Joël 
Published: August 2002

AbstractPreviously we described a transgenic mouse model in which neurofilaments are sequestered in neuronal cell bodies and withheld from the axonal compartment. This model and other transgenic models with disrupted neurofilaments are used widely to investigate the role of the neurofilament cytoskeleton in normal neurons and in inherited or acquired diseases. To interpret such studies, it is important to establish whether the maldistribution of neurofilaments has major secondary consequences on the cell biology of the affected neurons. Notably, multiple perturbations of the nervous system simultaneously affect both the neuronal cytoskeleton and neurotrophin expression. To determine whether the expression of neurotrophic factors or their receptors is perturbed by a primary disruption in neurofilaments, we compared the accumulated mRNA levels for ciliary neuroptrophic factor (CNTF), nerve growth factor, neurotrophin 3, and the α CNTF receptor in mature transgenic mice and their littermate controls. Consistently with the prolonged survival of neurons expressing atypical or abnormally distributed neurofilaments, no obvious changes were observed for any of the mRNA species examined. J. Neurosci. Res. 64:487–492, 2001. © 2001 Wiley‐Liss, Inc.
Are stronger North‐Atlantic southwesterlies the forcing to the late‐winter warming in Europe?
Authors: Otterman J. , Atlas R. , Chou S.‐H. , Jusem J. C. , Pielke R. A. , Chase T. N. , Rogers J. , Russell G. L. , Schubert S. D. , Sud Y. C. , Terry J. 
Published: August 2002

AbstractWe examine a possible mechanism leading to late‐winter warming, and thus to an early spring in Europe. From the National Centers for Environmental Prediction reanalysis, we extract for the years 1948–99 ocean‐surface winds over the eastern North Atlantic, and air temperatures at the surface Ts, and at the 500 hPa level T500 in late‐winter and spring. Ts is extracted at six European locations, all at 50.5°N, ranging in longitude from 1.9°E (northeastern France) to 26.2°E (Ukraine). To quantify the advection of maritime air into Europe, we evaluate for three‐pentad groups the index Ina of the southwesterlies at 45°N, 20°W; Ina is the average wind speed at this point if the direction is from the quadrant 180–270° (when the direction is different, the contribution counts as zero). In late winter, correlations Cit between Ina and Ts are substantial, up to the 0.6 level in western Europe (but weaker correlations for Poland and Ukraine). Cit drops sharply by mid‐March, occasionally taking negative values subsequently. This drop in Cit indicates that maritime air advection is no longer associated closely with the surface‐air warming; the role of insolation becomes important, and thus the drop in Cit marks the arrival of spring. Correlations CiΔ between Ina and our lapse‐rate parameter Δ, the difference between Ts and T500, indicate that the flow of warm maritime‐air from the North Atlantic into this ‘corridor’ at 50.5°N is predominantly at lower tropospheric level. By computing the best linear fit to Ina and Ts, the trends for the period 1948–99 are evaluated. The trends are appreciable in the second half of February and the first half of March: for Ina, the trends are 0.41 m s−1 and 0.15 m s−1 per decade in pentad groups 10–12 and 13–15 respectively (Ina increased from 1948 to 1999 by 2.10 m s−1 and 0.77 m s−1); for Ts, the trends for western Germany are 0.36°C and 0.43°C per decade in these two respective pentad groups (Ts in this location increased from 1948 to 1999 by 1.86°C and 2.19°C). Such higher near‐surface temperatures would markedly influence snow‐melt, and thus absorption of insolation by the surface. Our three‐pentad analysis points to the interval from mid‐February to mid‐March as the end of‐winter period in which the southwesterlies over the eastern North Atlantic become stronger and the surface‐air temperatures in Europe rise markedly, the lapse rate becomes steeper, and concurrently the longitudinal temperature gradient between the Somme (France) and the Oder (Germany–Poland border) (about −4°C in 1948 for the 10° longitude distance) is reduced by 0.8°C, i.e. by 20% of its 1948 value. Our thesis, that the observed late‐winter warming and the concomitant advancement of spring in Europe results, at least in part, from stronger southwesterlies over the North Atlantic, merits further investigations. Copyright © 2002 Royal Meteorological Society.
Effects of atmospheric circulation on ice conditions in the southern Baltic coastal lagoons
Authors: Girjatowicz Józef Piotr 
Published: August 2002

AbstractRelationships between atmospheric circulation patterns and ice conditions in the southern Baltic coastal lagoons were explored. Ice data consisted of number of ice days (L) and duration of ice season (S) in the Szczecin Lagoon (off Karnin), the Puck Bay (off Puck) and the Vistula Lagoon (off Krasnoflotskoye) from 1950/1951 to 1989/1990.Atmospheric circulation patterns for the period studied were extracted from Lityński's ‘Calendar of atmospheric circulation types’ developed at the Institute of Meteorology and Water Management (IMWM). A circulation pattern was identified by three numerical parameters: the zonal circulation index, the meridional circulation index, both pertaining to a zone delimited by coordinates 40–60°N, 0–35°E, and the surface pressure index for Warsaw.The number of days with individual atmospheric circulation patterns occurring from October to March was calculated. Subsequently, the selected patterns were combined by wind direction sectors and several month‐long periods that most closely correlated with ice conditions. The highest linear correlation coefficients (r>0.8) were obtained for the relationship between the number of days with winds from the east from December to February and December to March and the winter number of ice days (L). Somewhat higher were multiple correlation coefficients with winds from the east and west as circulation type predictors. Slightly lower correlation coefficients for the sectors and circulation periods mentioned were obtained for the duration of the ice season (S), although some of the coefficients were significant even at the probability level of α=0.01.Higher correlation coefficients were obtained for correlations involving ‘cold’ circulation patterns (sector NE+E+SE winds) and ice conditions than for those involving ‘warm’ patterns (sector SW+W+NW). Copyright © 2001 Royal Meteorological Society
Low‐temperature Raman spectra of polycrystalline NH4F and ND4F
Authors: Shurvell H. F. , Brown R. J. C. , Fredericks P. M. , Rintoul L. 
Published: August 2002

AbstractRaman spectra of polycrystalline ammonium fluoride and fully deuterated ammonium fluoride were recorded at various temperatures between 80 and 300 K. The spectra were obtained using a cold stage attached to a Raman microscope. At low temperatures the Raman lines were sharper and shifted to higher wavenumbers compared with their room temperature counterparts. However, no indications of any crystalline phase change were observed at low temperatures. A strong line at 2876 cm−1 was assigned to the infrared inactive symmetric NH stretching mode ν1(A1). A very strong line at lower wavenumbers (2818 cm−1) was assigned to the antisymmetric stretching mode ν3(F2). Observed deuterium isotope shifts were in agreement with those calculated using the Redlich–Teller isotope product rule. The degenerate bending modes ν2(E) and ν4(F2) were observed in the Raman spectra of NH4F and ND4F for the first time. The ν2 fundamental was split into doublets in the low‐temperature spectra, as predicted from a factor group analysis based on the known crystal structure. Three bands due to translational lattice modes were observed between 400 and 200 cm−1 in the spectra of both isotopic molecules. Several bands in both spectra are assigned to overtones and combinations involving an ammonium ion libration, but no bands directly attributable to ammonium ion librations were observed. Copyright © 2001 John Wiley & Sons, Ltd.
Feasibility of quantitative determination of doxorubicin with surface‐enhanced Raman spectroscopy
Authors: Lorén A. , Eliasson C. , Josefson M. , Murty K. V. G. K. , Käll M. , Abrahamsson J. , Abrahamsson K. 
Published: August 2002

AbstractSurface‐enhanced Raman spectroscopy (SERS) was performed using excitation at 488 nm in a blood plasma–doxorubicin–silver colloid system. With a blood plasma content of 1%, a partial least‐squares calibration of the doxorubicin was made in the 10–750 nM range. Predictions for a test set generated a root mean square error of prediction of 70 nM. The use of SERS and chemometrics in complex systems made it possible to use the highly informative Raman signals even at low concentrations without the need for sample pretreatment such as extraction. Copyright © 2001 John Wiley & Sons, Ltd.
Vibrational spectra and phase transition in Cd(CN)2·G clathrates [G = HCCl3, HCBr3, CH3CCl3, (CH3)3CCl or CHCl2CHCl2]
Authors: Kanesaka Isao , Kita Yuki , Nishikiori Shin‐Ichi 
Published: August 2002

AbstractVibrational spectra of Cd(CN)2·G clathrates were observed and changes in the spectral features with temperature analyzed, deducing phase transitions. A two‐step transition was found in the clathrates with G = HCCl3 (Tc = 188, 122 K), HCBr3 (249, 134 K) and CH3CCl3 (228, 154 K). The upper transition is ascribed to the ordering of the three‐site structure, pointing out similarity in the manner of interaction between the clathrates with C3v and Td guests. The lower transition is of a new type, which is considered to be an ordering process of dipoles. In Cd(CN)2·CHCl2CHCl2 a phase transition was found at 160 K. Its low transition temperature is ascribed to the difference in disordered structures between the C3v and CHCl2CHCl2 systems. 2H NMR spectral features of Cd(CN)2·DCCl3 are reported. Copyright © 2002 John Wiley & Sons, Ltd.
Raman mapping in the elucidation of solid salt eutectic and near eutectic structures
Authors: Berg Rolf W. , Kerridge David H. 
Published: August 2002

AbstractThe distribution of the different components of solidified eutectic or near‐eutectic salt mixtures (eutectics) was examined by use of Raman microscope mapping of the structures formed when these melts were slowly cooled. Seven binary and one ternary system were investigated. In most cases the component crystallized phases consisted of roughly rounded areas of about 0.5–5 µm across, the areas alternating in all directions across the sections. These three‐dimensional structures may best be described by the term ‘conglomerate.’ The size of these areas depended on the cooling rate and the composition. When unidirectional cooling was applied it was possible for the system (KCl–Na2SO4, 60 : 40 mol/mol) to observe lamellar arrangements of the component phases, in an arrangement closely similar to what is frequently found among metallic or ceramic eutectics. Each area, conglomerate or lamellar, did not consist of a pure chemical component, although having one component in a high concentration. Probably the behaviour represents separation on solidification due to the limiting solid solubility. The ‘conglomerate’ structures are very different from what has been found for metallic or ceramic eutectics. Small changes in composition, in sectioning direction and in solidification technique were found to result in relatively small differences. The major effect was found to result from the rate of solidification, faster cooling causing markedly smaller rounded areas with the ‘conglomerate’ becoming much finer grained. The high area of ‘interphasial’ contact between the solid solutions is considered to be responsible for the unexpectedly high electrical conductivity previously found and to give rise to part of the melting enthalpy differences between those of solidified salt eutectics and those of the corresponding unmelted mechanical mixtures of the component salts. Mixtures with a larger variation away from the eutectic composition also showed a ‘conglomerate’ structure, but with bigger and more irregular areas. Copyright © 2002 John Wiley & Sons, Ltd.
Phytosterols–what plant breeders should focus on
Authors: Miettinen Tatu A 
Published: August 2002

AbstractThe present paper compares effects of plant stanol and sterol esters on metabolism of cholesterol and plant sterols in studies designed to lower serum cholesterol in man. The ultimate aim is to emphasize factors on which plant breeders should focus when trying to develop new nutritionally interesting plant products for effective lowering of serum cholesterol and plant sterol levels. The findings indicate that fat solubility of phytostanol esters followed by their effective intestinal hydrolysis, preferentially of unsaturated fatty acid esters, allows sufficient micellar solubilization of unesterified plant stanols for prevention of cholesterol and plant sterol absorption, and subsequent lowering of their serum concentrations. Plant sterol esters apparently result in similar changes but, in contrast to stanol esters, increase their own absorption. Resulting increased serum plant sterol levels could occasionally approach values seen in phytosterolemia, a strongly atherogenic hereditary metabolic abnormality. Thus, plants producing oils rich in plant stanols esterified with unsaturated fatty aids would be preferable for preparation of functional foods with roughly 2 g/day of plant stanols in reasonable low amounts of calories.© 2001 Society of Chemical Industry.