bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alterations in the expression of antioxidant genes and the levels of transcription factor NF‐Kappa B in relation to diabetic embryopathy in the cohen diabetic rat model
Authors: Zangen Sarah W. , Ryu Seonghun , Ornoy Asher 
Published: February 2006

AbstractBACKGROUNDWe have previously shown that oxidative stress is important in the pathogenesis of diabetes‐induced anomalies in Cohen Diabetic sensitive (CDs) rat embryos and seems to interplay with genetic factors. We investigated the role of genetic factors related to the antioxidant defense mechanism in CDs rat embryos.METHODSWe studied 11.5‐ and 12.5‐day embryos of Cohen Diabetic resistant (CDr) and CDs rats that were fed a regular diet (RD), and hence not diabetic, compared to rats fed a high‐sucrose low‐copper diet (HSD) where only the CDs animals became diabetic. Embryos were monitored for growth and congenital anomalies. mRNA of catalase (CAT), glutathione peroxidase (GSHpx), CuZn‐SOD (SOD‐superoxide dismutase), and Mn‐SOD and the extent of nuclear factor kappa B (NF‐κB) activation were assessed.RESULTSEmbryos of CDs dams fed RD were significantly smaller and had an increased rate of NTDs compared to embryos of CDr dams fed RD. When CDs dams were fed HSD, >50% of the CDs embryos were dead and 44% of the live embryos had NTDs. Live 11.5‐day old embryos of CDs dams fed RD had a statistically significant increase in CAT, CuZn‐SOD, and GSHpx mRNA levels compared with the levels in the CDr embryos from dams fed RD. CDs embryos from dams fed HSD showed significant overactivation of NF‐κB compared with CDr embryos from dams fed HSD (in which activation was decreased), without any increase in the expression of SOD, CAT, and GSHpx.CONCLUSIONSThis study demonstrates that one of the genetic differences between the CDr and CDs strains fed RD is an increased expression of genes encoding for antioxidant enzymes in the CDs but inability for upregulation in diabetes. In addition, while activation of NF‐κB is decreased in CDr on HSD, it is increased in the CDs. These differences may play a role in the increased sensitivity of the CDs embryos to diabetic‐induced teratogenicity. Birth Defects Research (Part A), 2006. © 2006 Wiley‐Liss, Inc.
Mouse embryonic stem cells are not susceptible to cytomegalovirus but acquire susceptibility during differentiation
Authors: Matsukage Shoichi , Kosugi Isao , Kawasaski Hideya , Miura Katsutoshi , Kitani Hiroshi , Tsutsui Yoshihiro 
Published: February 2006

AbstractBACKGROUNDCytomegalovirus (CMV) is the most significant infectious cause of congenital anomalies of the central nervous system caused by intrauterine infection in humans. The timing of infection and the susceptibility of cells in early gestational stages are not well understood. In this study we investigated the susceptibility of embryonic stem (ES) cells to CMV infection during differentiation.METHODSES cell lines were established from transgenic mice integrated with the murine CMV (MCMV) immediate‐early (IE) promoter connected with a reporter lacZ gene. The susceptibility of the ES cells was analyzed in terms of viral gene expression and viral replication after induction of differentiation.RESULTSES cells were nonpermissive to MCMV infection in the undifferentiated state. Upon differentiation, permissive cells appeared ∼2 weeks after the leukemia inhibitory factor was removed. Upon neural differentiation by retinoic acid (RA), glial cells showed specific susceptibility in terms of expression of the viral antigen. The MCMV IE promoter was not activated in ES cells from the transgenic mice. Activation of the IE promoter was detected ∼2 weeks after induction of differentiation and observed predominantly in glial cells. Upon MCMV infection of the ES cells, viral infection was correlated with the activation of the IE promoter.CONCLUSIONSES cells are nonpermissive to MCMV infection and acquire permissiveness about 2 weeks after induction of differentiation, especially in glial cells. Acquisition of permissiveness in differentiated ES cells may be associated with activation of the IE promoter. Birth Defects Research (Part A), 2006. © 2006 Wiley‐Liss, Inc.
Efficacy and safety of radiofrequency ablation for perivascular hepatocellular carcinoma without hepatic inflow occlusion
Authors: Ng K K , Poon R T , Lam C M , Yuen J , Tso W K , Fan S T 
Published: February 2006

Abstract

Background
The role of radiofrequency ablation (RFA) for perivascular (up to 5 mm from the major intrahepatic portal vein or hepatic vein branches) hepatocellular carcinoma (HCC) is unclear because of possible incomplete tumour ablation and potential vascular damage. This study aimed to evaluate the safety and efficacy of RFA for perivascular HCC without hepatic inflow occlusion.

Methods
Between May 2001 and November 2003, RFA using an internally cooled electrode was performed on 52 patients with perivascular HCC (group 1) through open (n = 39), percutaneous (n = 9), laparoscopic (n = 2) and thoracoscopic (n = 2) approaches. Hepatic inflow occlusion was not applied during the ablation procedure. The perioperative and postoperative outcomes were compared with those of 90 patients with non-perivascular HCC (group 2) treated by RFA during the same period.

Results
The morbidity rate was similar between groups 1 and 2 (25 versus 28 per cent; P = 0·844). One patient in group 1 (2 per cent) and two in group 2 (2 per cent) had developed thrombosis of major intrahepatic blood vessels on follow-up computed tomography scan. There were no significant differences between groups 1 and 2 in mortality rate (2 versus 0 per cent; P = 0·366), complete ablation rate for small HCC (92 versus 98 per cent; P = 0·197), local recurrence rate (11 versus 9 per cent; P = 0·762) and overall survival (1-year: 86 versus 87 per cent; 2-year: 75 versus 75 per cent; P = 0·741).

Conclusion
RFA without hepatic inflow occlusion is a safe and effective treatment for perivascular HCC.
Routine surgical pathology in general surgery
Authors: Matthyssens L E , Ziol M , Barrat C , Champault G G 
Published: February 2006

Abstract

Background
Although pathological analysis provides the definitive diagnosis for most resection specimens, recent evidence suggests that such analysis may be omitted for certain routine samples. This was a retrospective analysis of the value of routine histopathological examination performed in daily general surgical practice.

Methods
All specimens from routine appendicectomies, cholecystectomies, haemorrhoidectomies and inguinal hernia repairs performed between 1993 and 2002 were included. The analysis included a comparison of histological and macroscopic diagnoses, review of preoperative and peroperative findings, and an evaluation of the consequences of routine histopathological assessment on patient management and costs.

Results
With the exception of hernia specimens, the rate of submission for routine pathological evaluation was 100 per cent. No hernia sac specimen from more than 2000 interventions revealed aberrant histological findings. Of 311 haemorrhoidectomy specimens three showed malignancy, all of which had a suspicious macroscopic appearance. Of 1465 appendices, only one (0·1 per cent) had a potentially relevant histological diagnosis that was not suspected macroscopically. Among 1523 cholecystectomy specimens, all adenomas (0·6 per cent) and carcinomas (0·4 per cent) were suspected macroscopically or developed in association with a known disease.

Conclusion
The rarity of incidental histological findings relevant to patient management, especially in the absence of macroscopic abnormalities, suggests that routine histological examination of certain specimens may be omitted. A more elementary role for macroscopic examination of the specimen by the surgeon and the pathologist is proposed.
The effect of temperature on the analysis of metanephrine for catechol‐O‐methyltransferase activity assay by HPLC with electrochemical detection
Authors: Passarinha L. A. , Bonifácio M. J. , Queiroz J. A. 
Published: February 2006

AbstractThe enzyme catechol‐O‐methyltransferase (COMT) plays an important role in the metabolism of catechol estrogens and degradation of the catecholamine neurotransmitters, such as epinephrine. Several analytical methods, mainly high‐performance liquid chromatography with electrochemical amperometric detection, have been reported for the analysis of catecholamines and their metabolites in biological fluids. In this paper we report the relevance of controlling temperature in calibration procedures of metanephrine, an O‐methylated product of catechol‐O‐methyltransferase, using epinephrine as substrate. The results at higher temperatures show shorter retention times of metanephrine, no undue band‐broadening and increased electro signals. This study also showed that, despite different temperatures leading to similarly specific activities of recombinant human COMT as expected, there are additional advantages in flow analytical methods where good sensitivity, efficiency and selectivity is required, mainly in tissues with low levels of COMT activity. Copyright © 2006 John Wiley & Sons, Ltd.
Implementation of 3D mesh streaming and compression techniques in NVEs
Authors: Bouras Christos J. , Panagopoulos Alexandros , Tsiatsos Thrasyvoulos 
Published: February 2006

AbstractIn this paper, we present a framework that integrates three‐dimensional (3D) mesh streaming and compression techniques and algorithms into our EVE‐II networked virtual environments (NVEs) platform, in order to offer support for large‐scale environments as well as highly complex world geometry. This framework allows the partial and progressive transmission of 3D worlds as well as of separate meshes, achieving reduced waiting times for the end‐user and improved network utilization. We also present a 3D mesh compression method focused on network communication, which is designed to support progressive mesh transmission, offering a fast and effective means of reducing the storage and transmission needs for geometrical data. This method is integrated in the above framework and utilizes prediction to achieve efficient lossy compression of 3D geometry. Copyright © 2006 John Wiley & Sons, Ltd.
Hydraulic erosion
Authors: Beneš Bedřich , Těšínský Václav , Hornyš Jan , Bhatia Sanjiv K. 
Published: February 2006

AbstractThis paper presents a generalized solution to modelling hydraulic erosion using ideas from fluid mechanics. The model is based on the Navier–Stokes equations, which provide the dynamics of velocity and pressure. These equations form the basis for the model to balance erosion and deposition that determine changes in the layers between water and erosion material. The eroded material is captured and relocated by water according to a material transport equation. The resulting model is fully 3D and is able to simulate a variety of phenomena including river meanders, low hill sediment wash, natural water springs and receding waterfalls. The simulations show the terrain morphogenesis and can be used for animations as well as for static scene generation. Copyright © 2006 John Wiley & Sons, Ltd.
Chloroplastic Glycolipids Fuel Aldehyde Biosynthesis in the Marine Diatom Thalassiosira rotula
Authors: Cutignano Adele , d'Ippolito Giuliana , Romano Giovanna , Lamari Nadia , Cimino Guido , Febbraio Ferdinando , Nucci Roberto , Fontana Angelo 
Published: February 2006

AbstractEnzymatic preparations and specialized analytical tools have shown that chloroplast‐derived glycolipids are the main substrates for the biosynthetic pathway that produces antiproliferative polyunsaturated aldehydes in broken cells of the marine diatom Thalassiosira rotula. This process, which is associated with the formation of free fatty acids and lyso compounds from polar lipids but not triglycerides, is largely dependent on glycolipid hydrolytic activity, rather than phospholipase A2 as previously suggested. Preliminary characterization of lipolytic enzymes has revealed protein bands of 40–45 kDa. Under native conditions these proteins seem to be associated with soluble aggregates that have an apparent molecular weight of approximately 200 kDa. The biochemical process, which is similar to that described in the algal‐bloom forming diatom Skeletonema costatum, suggests a mechanism based on decompartmentalization and mixing of preexisting enzymes and substrates.
Aminopeptidase P Mediated Detoxification of Organophosphonate Analogues of Sarin: Mechanistic and Stereochemical Study at the Phosphorus Atom of the Substrate
Authors: Huang Li‐Fang , Su Benson , Jao Shu‐Chuan , Liu Kwang‐Ting , Li Wen‐Shan 
Published: February 2006

AbstractThe activity of the aminopeptidase P from Escherichia coli in hydrolyzing a series of organophosphonate sarin analogues (1–6) was evaluated. The enzymatic rates of hydrolysis for methylphosphonate 1 with a methoxy group attached to the phosphorus center were 7‐ to 15‐fold higher than those for the corresponding analogues 2–6. Double mutant R153W/R370L was able to hydrolyze the Sp enantiomer of racemic 1 at a considerable rate. This mutant allowed the preparation of the Rp isomer of the sarin analogue 1. All the mutants, R370L, R153A, W88L, R153L/R370L, and R153W/R370L, preferred the formation of (Sp)‐8 to that of the corresponding (Rp)‐8 enantiomer and displayed a better enantiomeric excess of products, by 1.4‐ to 2‐fold as compared to the wild‐type enzyme. Enzymatic hydrolysis of O,O‐diisopropyl‐p‐nitrophenyl phosphate (9) in H218O led to the formation of the 18O‐labeled O,O‐diisopropyl phosphate product and confirmed that the catalytic reaction starts with cleavage of the PO bond. From chemical and kinetic studies, the utilization of an optically pure Sp enantiomer of O‐methyl‐p‐nitrophenyl methylphosphonothioate ((Sp)‐MNMPT, 7) has demonstrated that the enzymatic reaction proceeds through a displacement mechanism and generates a chiral product in situ with an inversion of stereochemical configuration at the phosphorus atom. The results also lead to the conclusion that alteration of the active site through site‐directed mutagenesis can result in a preference for (Sp)‐MNMPT (7) rather than the Rp isomer.
The Structural Basis for Docking in Modular Polyketide Biosynthesis
Authors: Weissman Kira J. 
Published: February 2006

AbstractPolyketide natural products such as erythromycin and rapamycin are assembled on polyketide synthases (PKSs), which consist of modular sets of catalytic activities distributed across multiple protein subunits. Correct protein–protein interactions among the PKS subunits which are critical to the fidelity of biosynthesis are mediated in part by “docking domains” at the termini of the proteins. The NMR solution structure of a representative docking domain complex from the erythromycin PKS (DEBS) was recently solved, and on this basis it has been proposed that PKS docking is mediated by the formation of an intermolecular four‐α‐helix bundle. Herein, we report the genetic engineering of such a docking domain complex by replacement of specific helical segments and analysis of triketide synthesis by mutant PKSs in vivo. The results of these helix swaps are fully consistent with the model and highlight residues in the docking domains that may be targeted to alter the efficiency or specificity of subunit–subunit docking in hybrid PKSs.
Frontal Polymerization Synthesis of Starch‐Grafted Hydrogels: Effect of Temperature and Tube Size on Propagating Front and Properties of Hydrogels
Authors: Yan Qing‐Zhi , Zhang Wen‐Feng , Lu Guo‐Dong , Su Xin‐Tai , Ge Chang‐Chun 
Published: February 2006

AbstractThe frontal polymerization process was used to produce superabsorbent hydrogels based on acrylic acid monomers grafted onto starch. Using a simple test tube which was nonadiabatic and permitted contact with air, the effects of initial temperature and tube size on the propagating front of grafting copolymerization and the properties of hydrogels were explored. The unrestricted access of the reaction mixture to oxygen delayed the formation of self‐propagating polymerization front. The ignition time was markedly lengthened with the increasing of tube size attributed to the formation of large amounts of peroxy radicals. The front velocity dependence on initial temperature could be fit to an Arrhenius function with the average apparent activation energy of 24 kJ mol−1, and on tube size to a function of higher order. The increase of the initial temperature increased the front temperature, which lead to more soluble oligomers and higher degree of crosslinking. The interplay of two opposite effects of oligomer and crosslinking determined the sol and gel content. An increase in tube size had two effects on the propagating front. One was to reduce heat loss. The other effect was to increase the number of escaping gas bubbles. The combined action of the two effects resulted in a maximum value of front temperature, an increase in sol content and a reduction in gel content with tube size. The highest swelling capacity of hydrogels was obtained when the initial temperature or tube size favored a formation of porous microstructure of hydrogels.
Helical Stacking Tuned by Alkoxy Side Chains in π‐Conjugated Triphenylbenzene Discotic Derivatives
Authors: Bao Chunyan , Lu Ran , Jin Ming , Xue Pengchong , Tan Changhui , Xu Tinghua , Liu Guofa , Zhao Yingying 
Published: February 2006

AbstractWe report on the synthesis and self‐assembly of a new series of discotic molecules containing triphenylbenzene as the core and alkoxy side chain with varying length. It was found that compounds 3 a–c, 4 b and 5 b could form stable gels in several apolar solvents. Transmission electron microscopy (TEM) images revealed that their morphologies were very different for the different alkoxy‐substituted organogels. In toluene or hexane, 3 b and 3 c resulted in both left‐ and right‐handed helical fibers, whereas 3 a resulted in straight rigid fibers; 4 b and 5 b resulted in most straight fibers with a few twisted fibers. The results from FT‐IR and UV/Vis absorption spectroscopy indicated that the hydrogen bonding and π–π interactions were the main driving forces for the formation of the self‐assembled gels. Further detailed analysis of their aggregation modes were conducted by UV‐visible absorption spectra and X‐ray diffraction (XRD) measurements. Based on these findings, the influence of these peripheral alkoxy substituents on the gel formation and the aggregation mode were discussed. The special enhanced fluorescent emissions, which resulted from aggregation, were also found in the gel phase.
Wire‐Type Ruthenium(II) Complexes with Terpyridine‐Containing [2]Rotaxanes as Ligands: Synthesis, Characterization, and Photophysical Properties
Authors: Davidson Gregory J. E. , Loeb Stephen J. , Passaniti Paolo , Silvi Serena , Credi Alberto 
Published: February 2006

Abstract[2]Rotaxanes based on the 1,2‐bis(pyridinium)ethane⊂[24]crown‐8 ether motif were prepared that contain a terminal terpyridine group for coordination to a transition‐metal ion. These rotaxane ligands were utilized in the preparation of a series of heteroleptic [Ru(terpy)(terpy–rotaxane)]2+ complexes. The compounds were characterized by 1D and 2D 1H NMR spectroscopy, X‐ray crystallography, and high‐resolution electrospray ionization mass spectrometry. The effect of using a rotaxane as a ligand was probed by UV/Vis/NIR absorption and emission spectroscopy of the RuII complexes. In contrast with the parent [Ru(terpy)2]2+ complex, at room temperature the examined complexes exhibit a luminescence band in the near infrared region and a relatively long lived triplet metal‐to‐ligand charge‐transfer (3MLCT) excited state, owing to the presence of strong‐electron‐acceptor pyridinium substituents on one of the two terpy ligands. Visible‐light excitation of the Ru‐based chromophore in acetonitrile at room temperature causes an electron transfer to the covalently linked 4,4′‐bipyridinium unit and the quenching of the MLCT luminescence. The 3MLCT excited state, however, is not quenched at all in rigid matrix at 77 K. The rotaxane structure was found to affect the absorption and luminescence properties of the complexes. In particular, when a crown ether surrounds the cationic axle, the photoinduced electron‐transfer process is slowed down by a factor from 2 to 3. Such features, together with the synthetic and structural advantages offered by [Ru(terpy)2]2+‐type complexes compared to, for example, [Ru(bpy)3]2+‐type compounds, render these rotaxane–metal complexes promising candidates for the construction of photochemical molecular devices with a wire‐type structure.
Metal Nuclearity Modulated Four‐, Six‐, and Eight‐Connected Entangled Frameworks Based on Mono‐, Bi‐, and Trimetallic Cores as Nodes
Authors: Wang Xin‐Long , Qin Chao , Wang En‐Bo , Su Zhong‐Min 
Published: February 2006

AbstractTo investigate the relationship between network connectivity and metal nuclearity, we designed and synthesized a series of three‐dimensional (3D) entangled coordination frameworks based on different metal cores, namely [Zn2(bdc)2(L)2]⋅2H2O (1), [Zn(bdc)(L)0.5] (2), [Zn(oba)(L)0.5] (3) and [Cd3(bdc)3(L)2(H2O)2] (4) by self‐assembly of d10 metal salts with the flexible long‐chain ligand 1,4‐bis(1,2,4‐triazol‐1‐yl)butane (L), and with the rigid and nonrigid aromatic dicarboxylate ligands 1,4‐benzenedicarboxylate (bdc) and 4,4′‐oxybis(benzoate) (oba). Compound 1 exhibits a threefold interpenetrated diamondoid array typically based on a tetrahedral second building unit (SBU) at a single Zn center. Compound 2 adopts a threefold interpenetrated α‐polonium‐type network that is built from bimetallic cores as six‐connected vertices. The structure of 3 also consists of dinuclear units; it comprises a novel (3,4)‐connected threefold interpenetrated net with complex (4⋅6⋅10)(4⋅62⋅103) topology when single zinc centers act as four‐connected nodes (or the α‐Po topology if dinuclear units are considered as six‐connected nodes). Compound 4, derived from a crosslinked fivefold interpenetrated diamond‐like substructure, is an unusual example of a self‐penetrating coordination framework displaying an unprecedented eight‐connected 42068 topology with trinuclear cadmium clusters as eight‐connected nodes which, to our knowledge, not only defines a new topology for eight‐connected coordination networks, but also represents the highest connected topology presently known for self‐penetrating systems. Detailed structural comparison of these complexes indicates that the increase in metal nuclearity induces the progressive increase in the connectivities of the ultimate nets: that is, the metal nuclearity plays a significant role in tuning the connectivity of a specific network. The thermal and luminescent properties of these compounds are discussed.
Synthesis of 7‐Deoxypancratistatin from Carbohydrates by the Use of Olefin Metathesis
Authors: Håkansson Anders E. , Palmelund Anders , Holm Henriette , Madsen Robert 
Published: February 2006

AbstractThe stereocontrolled synthesis of (+)‐7‐deoxypancratistatin is described. The convergent synthesis has been achieved by two different strategies, both of which commence from a pentose and piperonal. The latter is converted into allylic bromide 7, which is then coupled with a protected methyl 5‐deoxy‐5‐iodo‐D‐ribofuranoside in the presence of zinc metal. The first strategy involves a total of only 13 steps from D‐ribose and piperonal, but suffers from a low yield in the zinc‐mediated reaction between ribofuranoside 9, benzylamine, and bromide 7. The second strategy involves a total of 18 steps from D‐xylose and piperonal. The former is converted into ribofuranoside 28, which is coupled with bromide 7 in the presence of zinc, and this is followed by ring‐closing olefin metathesis. Subsequent Overman rearrangement, dihydroxylation, and deprotection then affords the natural product.
K5[FeO4] and K17[Fe5O16]: Two New Potassium Oxoferrates(III).
Authors: Frisch Gero , Roehr Caroline 
Published: February 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.