bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Potassium Complexes Containing Terminal η2‐Pyrazolato Ligands
Authors: Zheng Wenjun , Heeg Mary Jane , Winter Charles H. 
Published: April 2004

AbstractThe potassium complexes [K(η2‐3,5‐R2pz)(η6‐18‐crown‐6)] (R = Ph, tBu; pz = pyrazolato) were prepared by treatment of 3,5‐diphenylpyrazole or 3,5‐di‐tert‐butylpyrazole with potassium hydride in the presence of 18‐crown‐6. These complexes contain η6‐18‐crown‐6 and terminal η2‐pyrazolato ligands, and constitute the first examples of group 1 metal complexes with this pyrazolato ligand coordination mode. In contrast to [K(η2‐3,5‐Ph2pz)(η6‐18‐crown‐6)] and [K(η2‐3,5‐tBu2pz)(η6‐18‐crown‐6)], the aqua complex [K(η2‐3,5‐Me2pz)(H2O)(η6‐18‐crown‐6)] was obtained when 3,5‐dimethylpyrazole was treated with potassium hydride and 18‐crown‐6 in the presence of a small amount of water. [K(η2‐3,5‐Me2pz)(H2O)(η6‐18‐crown‐6)] contains an η2‐pyrazolato ligand that is bent towards being co‐facial with the best plane of the 18‐crown‐6 ligand, to allow hydrogen bonding between the pyrazolato ligand nitrogen atoms and the coordinated aqua ligand. The hydrogen bonding thus confers a novel terminal π‐facial η2‐bonding mode to the pyrazolato ligand. All compounds were characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Efficient Addition of Acid Enediolates to Epoxides
Authors: Gil Salvador , Torres Mercedes , Ortúzar Natalia , Wincewicz Richard , Parra Margarita 
Published: April 2004

AbstractWe report new conditions to facilitate the addition of dianions of carboxylic acids to epoxides as an alternative method to the use of aluminum enolates. These conditions require the use of a sub‐stoichiometric (10%) amount of amine for dianion generation and the previous activation of the epoxide with LiCl. Other Lewis acids have been shown to be less effective. Yields are good but only low diastereoselectivity is attained, which has not been controlled despite attempts at optimization. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Lower targets for weekly weight gain lead to better results in inpatient treatment of anorexia nervosa: a pilot study
Authors: Herzog Thomas , Zeeck Almut , Hartmann Armin , Nickel Thomas 
Published: April 2004

AbstractObjectiveTo compare the short‐term impact of different targets for minimum weekly weight gain (MWWG) in inpatient treatment for anorexia nervosa.MethodComparison of weight gain and its maintenance in 16 consecutively admitted anorexic patients with MWWG targeted at 750 g and in the subsequent 16 patients with MWWG targeted at 500 g.ResultsBoth groups were characterized by severely ill anorexic patients who were comparable on most measures. A total of 69 and 81 per cent, respectively, reached target weight (m = 18.3 (SD = 0.4) kg/m2). During the subsequent 10 weeks under standardized inpatient conditions, 12 of 13 achievers in the 500 g per week group maintained or increased their weight compared to only three of 11 in the 750 g per week group (p ≤ 0.002).DiscussionLower rather than higher MWWG targets under a clear symptom focus may be advantageous regarding the short‐term symptomatic improvement of anorectic patients. The findings raise important questions regarding weight gain and its regulation on the biological (e.g. leptin system), psychological and social levels. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
The impact of a four‐month day treatment programme on alexithymia in eating disorders
Authors: Becker‐Stoll Fabienne , Gerlinghoff Monika 
Published: April 2004

AbstractHigh prevalence rates of alexithymia have been reported in eating‐disordered patients. The aim of this study was first to investigate whether a 4‐month day hospital treatment leads to a decrease in alexithymia in eating‐disordered patients and second to see whether alexithymia predicts short‐term outcome in this population. The Toronto Alexithymia Scale (TAS) and the Eating Disorder Inventory (EDI) were given to 47 patients with anorexia nervosa (n = 18), bulimia nervosa (n = 25) and eating disorders not otherwise specified (n = 4) respectively at the beginning and at the end of a 4‐month treatment programme. Comparison of pre‐ and post‐treatment scores showed significant declines in the EDI as well as in the TAS. However, baseline scores for alexithymia did not predict post‐treatment outcome. We conclude that even highly alexithymic patients benefit from psychological treatment which encourages understanding and expressions of emotion and also leads to significant reduction in eating disorder‐related symptoms. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Chemie freier cyclischer vicinaler Tricarbonyl‐Verbindungen (‘1,2,3‐Trione’). Teil 3
Authors: Schank Kurt , Lieder Robert , Lick Carlo , Glock Rebecca 
Published: April 2004

AbstractChemistry of Free Cyclic Vicinal Tricarbonyl Compounds (‘1,2,3‐Triones’). Part 3. Polar and Redox Reactions of 1,2,3‐Triones with Enamines of Different Types – News on Oxonol Dyes, Radicals, and Biradicals The central CO groups of cyclic 1,2,3‐triones possess outstanding electrophilic (electron‐pair‐accepting) as well as oxidizing (one‐electron‐accepting) properties. Thus, 1,2,3‐triones are chemically related to 1,2‐ and 1,4‐benzoquinones. Whereas polar reactions with carbanion‐like (electron rich) species give rise to nucleophilic addition reactions to CO groups under exclusive C,C‐bond formation, SET (single‐electron transfer) or redox reactions effect a partial ‘carbonyl Umpolung’ via ketyl intermediates (C,C‐ and/or C,O‐bond formation). Here, we report on numerous reactions between electron‐rich, more‐ or less‐polar enamines with 5,5‐dimethylcyclohexane‐1,2,3‐trione (9a) and 1H‐indene‐1,2,3‐trione (9b). Various new derivatives of basic oxonol dyes were formed, including the first oxonol dye incorporating a 1,3‐dioxocyclohexyl moiety. A novel stable radical, 50/50′, was obtained from 9b and 11a via addition, hydrolysis, and treatment with conc. H2SO4. Radical 50/50′ represents a vinylogous ‘monodehydroreductone’ and is, thus, related to monodehydroascorbic acid (143), to Russell's radical cation (144), to indigo (141/141′), and to quinhydrone.
Kopsifolines A–F: a New Structural Class of Monoterpenoid Indole Alkaloids from Kopsia
Authors: Kam Toh‐Seok , Choo Yeun‐Mun 
Published: April 2004

AbstractSix new indole alkaloids, named kopsifolines A–F (1–6), with an unprecedented hexacyclic carbon skeleton, constituting a new structural group of monoterpenoid indole alkaloids, were obtained from the leaf extract of a Malayan Kopsia species, and their structures were established by spectroscopic analysis.
Biomaterial surface‐dependent neutrophil mobility
Authors: Zhou Yue , Doerschuk Claire M. , Anderson James M. , Marchant Roger E. 
Published: April 2004

AbstractCompromised neutrophil function in the presence of an implanted biomaterial may represent an important mechanism that allows for the development of implant‐associated infections. Here, human neutrophil mobility has been investigated on a polyurethane (ChronoFlex AR), a hydrophobic surface consisting of an octadecyltrichlorosilane (OTS) self‐assembled monolayer, and a glass reference material. Neutrophil mobility was quantified, based on cell movement speed and persistence time obtained from time‐lapse optical microscopy, while neutrophil cytoskeletal structures and morphology were visualized using confocal microscopy and atomic force microscopy. Our results show that material surface properties affect neutrophil–surface interactions, as reflected by morphological changes, and the mobility of neutrophils stimulated by N‐formylmethionyl‐leucyl‐phenylalanine (fMLP). In the absence of adsorbed plasma proteins, the mobility of stimulated neutrophils increased with increasing material hydrophobicity from glass, to polyurethane, to OTS. The opposite trend was observed in the presence of adsorbed plasma proteins, such that neutrophil mobility increased with decreasing material hydrophobicity. Analysis of the results showed that the mobility of fMLP‐stimulated neutrophils cells was inversely related to the extent of cell spreading on the materials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 611–620, 2004
A new method to locate saddle points for reactions in solution by using the free‐energy gradient method and the mean field approximation
Authors: Galván I. Fdez. , Martín M. E. , Aguilar M. A. 
Published: April 2004

AbstractA new method for calculating saddle points of reactions in solution is presented. The main characteristics of the method are: (1) the solute–solvent system is described by the averaged solvent electrostatic potential/molecular dynamics method (ASEP/MD). This is a quantum mechanics/molecular mechanics method (QM/MM) that makes use of the mean field approximation (MFA) and that permits one to simultaneously optimize the electronic structure and geometry of the solute molecule and the solvent structure around it. (2) The transition state is located by the joint use of the free‐energy gradient method and the mean field approximation. An application to the study of the Menshutkin reaction between NH3 and CH3Cl in aqueous solution is discussed. The accuracy and usefulness of the proposed method is checked through comparison with other methods. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1227–1233, 2004
Reaction pathways and projection operators: Application to string methods
Authors: Quapp Wolfgang 
Published: April 2004

AbstractThe reaction path is an important concept of theoretical chemistry. We discuss the definition with the help of diverse projection operators for the intrinsic reaction coordinate (IRC), for the following of the reduced gradient (RGF) or Newton trajectory (NT), and for the Gradient Extremal (GE). We describe different numerical schemes for the definitions in the context of string methods. It comes out that Newton trajectories are the best ansatz for a string method. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1277–1285, 2004
Mechanism for ribonucleotide reductase inactivation by the anticancer drug gemcitabine
Authors: Pereira Susana , Fernandes Pedro Alexandrino , Ramos Maria João 
Published: April 2004

AbstractGemcitabine (2′,2′‐difluoro‐2′‐deoxycytidine, dFdC) is a very promising anticancer drug, already approved for clinical use in three therapeutic indications. It is metabolized intracellularly to 5′‐diphosphate (dFdCDP), which is known to be a potent inhibitor of ribonucleotide reductase (RNR). Although several nucleotide analogs show in vitro capacity of RNR inactivation, none has shown the in vivo efficacy of dFdCDP. Accordingly, the experimental data suggests that its mechanism of inhibition is different from the other known RNR suicide inhibitors. Enzyme inhibition in the absence of reductive species leads to complete loss of the essential radical in subunit R2, and formation of a new nucleotide‐based radical. Interestingly, however, the presence of the reductants does not prevent inhibition—the radical is not lost but the targeted subunit of RNR becomes R1, which is inactivated possibly by alkylation. We have conducted a theoretical study, which led us to the first proposal of a possible mechanism for RNR inhibition by dFdCDP in the absence of reductants. This mechanism turned out to be very similar to the natural substrate reduction pathway and only deviates from the natural course after the formation of the well‐known disulphide bridge. This deviation is caused precisely by the F atom in the β‐face, only present in this inhibitor. The essential radical in R2 is lost, and so is the enzyme catalytic activity. The nucleotide‐based radical that constitutes the end product of our mechanism has been suggested in the literature as a possible candidate for the one detected experimentally. In fact, all experimental data available has been reproduced by the theoretical calculations performed here. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1286–1294, 2004
Prevalence of hepatitis A antibodies in schoolchildren in Catalonia (Spain) after the introduction of universal hepatitis A immunization
Authors: Domínguez Àngela , Bruguera Miquel , Plans Pere , Costa Josep , Salleras Lluís 
Published: April 2004

AbstractThe objective of this study was to investigate the prevalence of hepatitis A antibodies (anti‐HAV) in schoolchildren in Catalonia and to compare it with the rates found in previous studies. Sera from a representative sample of 1,342 children aged between 6 and 15 years, recruited in 2001, were tested for anti‐HAV. The results were related to sociodemographic variables and vaccination history. The overall prevalence of anti‐HAV was 51.4%. The prevalence was 5.5% in non‐vaccinated children, similar to that found in a 1996 study, and 96.6% in vaccinated children. The prevalence of anti‐HAV in non‐vaccinated children increased significantly with age, reaching 11.6% in the 13–15 years age group. The prevalence of anti‐HAV was higher in children born outside Catalonia than in those born in Catalonia (16.1% vs. 5.0%, P = 0.02). The expected continuation in the decline in the prevalence of anti‐HAV in non‐vaccinated schoolchildren, observed in Catalonia since 1986, was not found in 2001. The rate of anti‐HAV in 2001 was slightly higher than in 1996, although the difference was not statistically significant (5.5 and 3.5%, respectively). This could be explained by the increased number of recent immigrant children born outside Catalonia, mainly in countries where hepatitis A is highly endemic. J. Med. Virol. 73:172–176, 2004. © 2004 Wiley‐Liss, Inc.
Reduction of double‐stranded RNA‐activated protein kinase in hepatocellular carcinoma associated with hepatitis B virus
Authors: Chen George G. , Lai Paul B.S. , Ho Rocky L.K. , Chan Paul K.S. , Xu H. , Wong John , Lau Wan Y. 
Published: April 2004

AbstractChronic hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) in Asia. Double‐stranded RNA (dsRNA)‐activated protein kinase (PKR) is an interferon‐induced, serine/threonine protein kinase. Recent studies have suggested that PKR is involved in the pathogenesis of HCC with hepatitis virus C infection by inhibiting viral and cellular proteins related to cell growth and proliferation. In the present study, PKR was examined in both tumor and non‐tumor tissues from HCC livers infected with HBV. The expression of PKR was determined by TaqMan real‐time PCR and immunohistochemical methods. The level of PKR was also analyzed in relation to pathological changes observed in HCC. The result showed that PKR was reduced in tumor tissues of HCC from HBV carriers with low serum viral load (<0.7 × 106 copies/ml) compared to those with higher serum viral load. However, the overall PKR level was much lower in tumor tissues than that in non‐tumor tissues, irrespective of HBV carrier status or serum viral load. PKR level tended to be lower in HCC samples with alpha‐fetoprotein (AFP) more than 500 ng/ml (mean: 4024.2 ng/ml) than those with AFP less than 500 ng/ml (mean: 50.6 ng/ml). There was no significant difference in the expression of PKR between tumor tissues with well differentiation and those with poor or moderate differentiation. In conclusion, the level of PKR was reduced in HCC tumor tissues, suggesting a possible role of PKR in promoting the growth of tumor. HBV may participate in altering the level of PKR, but factors other than HBV should play a more determining role in the regulation of PKR in HCC. The association between PKR and AFP levels may offer an alternative tumor marker for HCC. J. Med. Virol. 73:187–194, 2004. © 2004 Wiley‐Liss, Inc.
Quantitation of cytomegalovirus DNA by the polymerase chain reaction as a predictor of disease in solid organ transplantation
Authors: Ghisetti Valeria , Barbui Anna , Franchello Alessandro , Varetto Silvia , Pittaluga Fabrizia , Bobbio Marco , Salizzoni Mauro , Marchiaro Giovanna 
Published: April 2004

AbstractCytomegalovirus (CMV) infection is an important cause of morbidity in solid organ recipients. Early markers to identify the progress of the infection and patients at high risk are required in order to apply a strategy of pre‐emptive therapy. The efficacy of pre‐emptive therapy relies on accurate laboratory tests to monitor CMV infection. The evaluation of CMV DNA kinetics by the polymerase chain reaction (PCR) is widely used for the management of CMV infection but markers predicting the progression of the infection and standardization of the technique are essential for the clinical interpretation of PCR results. A commercially available PCR system, the COBAS AMPLICOR Monitor (Roche Diagnostics, Brachburg, NJ), was used for the quantitation of CMV DNA in weekly blood samples (n = 504) from 47 solid organ recipients in the first 6 months after transplantation. PCR results were evaluated according to the development of clinical disease in order to find a DNA threshold and time points predicting the progression of CMV infection. Week 4 from transplantation was the earliest time point to note a significant difference between those patients who eventually developed CMV disease (n = 30) and those who remained asymptomatically infected (n = 17). At week 4, viral loads were significantly higher in patients who developed CMV disease than in asymptomatic infections (median value: 4 log10/106 leukocytes vs. 2.8, P < 0.0001). At week 4, a DNA level ≥4 log10/106 leukocytes was associated with a 45.37 odds ratio for CMV disease. Any increase ≥1 log from the first DNA detection to week 4 correlated with the clinical progression of CMV infection (odds ratio 1.74). In those patients who were treated with anti‐CMV therapy, a >97% reduction of the baseline viral load was associated with a complete therapeutic success. In conclusion, CMV infection is a highly dynamic process and the quantitation of CMV DNA by PCR is a powerful marker to control successfully the infection, but a strict follow‐up of the recipient and standardized PCR tests are mandatory for the best management of the infection. J. Med. Virol. 73:223–229, 2004. © 2004 Wiley‐Liss, Inc.
Variations in the serum concentrations of soluble Fas and soluble Fas ligand in Vietnamese patients infected with hepatitis B virus
Authors: Song Le H. , Binh Vu Q. , Duy Dinh N. , Bock Thomas C. , Kremsner Peter G. , Luty Adrian J.F. , Mavoungou Elie 
Published: April 2004

AbstractEarlier studies of both chronic hepatitis B and C virus (HBV and HCV) patients have shown a strong correlation between the soluble membrane Fas (sFas) and Fas protein expression on hepatocytes. The serum concentrations of sFas and soluble Fas ligand (sFasL) was examined in both healthy and HBV‐infected Vietnamese patients to determine their relationship with the outcome of HBV infection. Patients with chronic rather than acute HBV had significantly higher amounts of sFas and sFasL, whilst the highest concentrations of both molecules were detected in those with malignant forms of HBV infection. sFas and sFasL concentrations tended to increase with a profile that paralleled the progression from asymptomatic to acute through chronic to malignant states, most markedly in the case of sFas. The sFas:sFasL ratio highlighted the relative predominance of sFas in those with acute and chronic HBV compared with asymptomatic or severe forms. In patients with hepatocellular carcinoma (HCC) a significant correlation was also observed between sFasL and alpha‐feto protein (AFP) levels. The results indicate that sFas and to a lesser extent sFasL levels are to some degree associated with clinical progression in HBV infection. J. Med. Virol. 73:244–249, 2004. © 2004 Wiley‐Liss, Inc.
Acute retinal necrosis six years after herpes simplex encephalitis: An elusive immune deficit suggested by insufficient test sensitivity
Authors: Preiser W. , Doerr H.W. , Buxbaum S. , Rabenau H.F. , Baatz H. 
Published: April 2004

AbstractA patient presented with acute retinal necrosis of the left eye. Demonstration of herpes simplex virus (HSV) DNA in the aqueous humour confirmed the diagnosis. Negative results of HSV type‐specific antibody tests based on gG antigens suggested a primary HSV infection. However, the patient had a past history of laboratory‐confirmed herpes simplex encephalitis 6 years ago. Using antibody tests based on whole viral lysate antigens, he was seropositive from the onset, and immunoblot testing confirmed a lack of anti‐gG reactivity. To be able to assess whether this might be related to the apparent inability of his immune system to suppress clinically symptomatic HSV infection, serial samples were tested by an HSV neutralisation test and a whole‐blood flow cytometric assay to determine the frequency of HSV‐specific CD4 lymphocytes. However, this did not yield evidence of obvious immunodeficiency; the patient reacted similarly to known positive controls by both assays. Although type‐specific HSV serological tests based on gG are generally more specific than those based on whole viral lysate antigens, they have a somewhat lower sensitivity, as a certain percentage of HSV‐infected individuals do not develop antibodies against gG, and others may suffer a secondary loss of anti‐gG reactivity. Thus there is a risk of missing individual infected patients. Unless this potential problem is recognised, serious consequences might possibly result. We therefore urge virologists and clinicians to exercise great care if highly specific antibody assays based on recombinant proteins are employed. J. Med. Virol. 73:250–255, 2004. © 2004 Wiley‐Liss, Inc.
Vesicle transport in oligodendrocytes: Probable role of Rab40c protein
Authors: Rodriguez‐Gabin A.G. , Almazan G. , Larocca J.N. 
Published: April 2004

AbstractIntracellular membrane trafficking plays an essential role in the structural and functional organization of oligodendrocytes, which synthesize a large amount of membrane to form myelin. Rab proteins are key components in intracellular vesicular transport. We cloned a novel Rab protein from an oligodendrocyte cDNA library, designating it Rab40c because of its homology with Rab40a and Rab40b. The DNA sequence of Rab40c shows an 843‐base pair open reading frame. The deduced amino acid sequence is a protein with 281 amino acids, with a molecular weight of 31,466 Da and an isoelectric point of 9.83. Rab40c presents a number of distinct structural features including a carboxyl terminal extension and amino acid substitutions in the consensus sequence of the GTP‐binding motifs. The carboxyl terminal region contains motifs that permit isoprenylation and palmitoylation. Binding studies indicate that Rab40c binds guanosine 5′‐0‐(3‐thiotriphosphate) (GTPγS) with a Kdof 21 μM and has a higher affinity for guanosine triphosphate (GTP) than for guanosine diphosphate (GDP). Rab40c is localized in the perinuclear recycling compartment, suggesting its involvement in endocytic events such as receptor recycling. The importance of this recycling in myelin formation is suggested by the increase in both Rab40c mRNA and Rab40c protein as oligodendrocytes differentiate. © 2004 Wiley‐Liss, Inc.