bluuebunny/crossref_metadata_2025 huggingface dataset:
Metathesis Reactions in Total Synthesis
Authors: Nicolaou K. C. , Bulger Paul G. , Sarlah David
Published: July 2005

With the exception of palladium‐catalyzed cross‐couplings, no other group of reactions has had such a profound impact on the formation of carbon–carbon bonds and the art of total synthesis in the last quarter of a century than the metathesis reactions of olefins, enynes, and alkynes. Herein, we highlight a number of selected examples of total syntheses in which such processes played a crucial role and which imparted to these endeavors certain elements of novelty, elegance, and efficiency. Judging from their short but impressive history, the influence of these reactions in chemical synthesis is destined to increase.
Cover Picture: Palladium‐Catalyzed Cross‐Coupling Reactions in Total Synthesis / Metathesis Reactions in Total Synthesis (Angew. Chem. Int. Ed. 29/2005)
Authors: Nicolaou K. C. , Bulger Paul G. , Sarlah David
Published: July 2005

A powerful combination of two synthetic methods has advanced the art of organic synthesis like few other reactions. In their Reviews on page 4442 ff. and 4490 ff. K. C. Nicolaou and co‐workers illustrate how palladium‐catalyzed cross‐couplings and metathesis‐based reactions, respectively, have blossomed into powerful tools for carbon–carbon bond formation in the total synthesis of natural products.
Application of rice husk ash as fillers in the natural rubber industry
Authors: Arayapranee Wanvimon , Na‐Ranong Nuchanat , Rempel Garry L.
Published: July 2005

Rice husk ash (RHA) obtained from agricultural waste, by using rice husk as a power source, is mainly composed of silica and carbon black. A two‐stage conventional mixing procedure was used to incorporate rice husk ash into natural rubber. For comparison purposes, two commercial reinforcing fillers, silica and carbon black, were also used. The effect of these fillers on cure characteristics and mechanical properties of natural rubber materials at various loadings, ranging from 0 to 40 phr, was investigated. The results indicated that RHA filler resulted in lower Mooney viscosity and shorter cure time of the natural rubber materials. The incorporation of RHA into natural rubber improved hardness but decreased tensile strength and tear strength. Other properties, such as Young's modulus and abrasion loss, show no significant change. However, RHA is characterized by a better resilience property than that of silica and carbon black. Scanning electron micrographs revealed that the dispersion of RHA filler in the rubber matrix is discontinuous, which in turn generates a weak structure compared with that of carbon black and silica. Overall results indicate that RHA can be used as a cheaper filler for natural rubber materials where improved mechanical properties are not critical. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 34–41, 2005
An adsorption study of gelatin onto the Fuller's earth surfaces
Authors: Bajpai A. K. , Vishwakarma Nekshri
Published: July 2005

An adsorption study of gelatin was performed from its aqueous solution onto the Fuller's earth surfaces at room temperature. The dynamics of the adsorption process were followed spectrophotometrically; and various adsorption and kinetic parameters, such as adsorption coefficient, rate constants for adsorption and desorption, and penetration rate constant, were evaluated. The adsorption was found to vary sensitively with pH variation and show minima in both the media, that is, in acidic and basic. It was also observed that the presence of anions reversed their impact on adsorbed amount at their high concentration. The effect of cations and temperature were also investigated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 42–52, 2005
Wrinkling of epoxy powder coatings
Authors: Basu Soumendra K. , Scriven L. E. , Francis L. F. , McCormick A. V. , Reichert Veronica R.
Published: July 2005

Differential scanning calorimetry (DSC) and mechanical profilometry were used to study wrinkle formation in curing epoxy powder coatings. Powder coating formulations were studied that contained solid epoxy resins, methylene disalicylic acid (MDSA) crosslinker, and an amine‐blocked Lewis acid catalyst. Both the crosslinker (MDSA) and the amine‐blocked catalyst are required for wrinkle formation. Evaporation of the blocking amine from the free surface of the coating generated a depthwise gradient in the extent of polymerization and crosslinking, and hence in the degree of solidification, as evidenced by the formation of a mechanical skin prior to wrinkling. It is hypothesized that compressive elastic stress develops in the still swellable skin when unreacted low‐molecular‐weight material from beneath diffuses up into the monomer‐ or oligomer‐depleted crosslinking skin and swells it. This compressive stress, if above a critical value, buckles the skin to produce wrinkles. Experimentally observed compositional requirements for wrinkle formation were consistent with the proposed mechanism. The size of the wrinkles can be controlled by varying formulation parameters such as the amount of catalyst or crosslinker. Increasing the amount of catalyst decreased both the wavelength and the amplitude of the wrinkle pattern. Increasing the amount of crosslinker initially increased the amplitude of the wrinkles; after reaching a maximum level, the wrinkle amplitude decreased. DSC was a useful tool to understand the critical reactions responsible for wrinkling in this system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 116–129, 2005
Matrix effects on tubule distribution and dielectrics properties of tubule‐based dielectrics
Authors: Chiou Bor‐Sen , Lankford Andrew R. , Mera Ann E. , Zabetakis Dan , Schoen Paul E.
Published: July 2005

The dielectric properties of composites containing copper‐coated tubules in epoxy and polyurethane were characterized and interpreted in terms of contact angle and interfacial tension between the filler and the polymer matrix. The polyurethane samples had larger permittivity values than the epoxy samples over the entire tubule concentration range. The results suggested the tubules in polyurethane were more aggregated than those in epoxy and, consequently, the polyurethane samples were closer to percolation. This was inconsistent with the contact angle and interfacial tension data, because epoxy had larger contact angles and interfacial tension than polyurethane. Therefore, the contact angle and interfacial tension data could not be used to predict tubule distribution in composites. Also, the De Loor model provided a good fit to the permittivity data. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 53–57, 2005
Thermal degradation kinetics of poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)
Authors: Daly Patricia A. , Bruce David A. , Melik David H. , Harrison Graham M.
Published: July 2005

The degradation kinetics of poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate), a member of the Nodax family of polymers, were investigated using transient constant shear rate and dynamic time sweep rheological tests. The rate of chain scission at several times and temperatures was correlated with viscosity data and verified using molecular weight determination of the degraded samples. The experimental results show that the molecular weight and the viscosity of Nodax decrease with time over the range of temperatures that were studied (155–175°C). The degradation kinetics, which exhibited first‐order behavior, were determined as a function of the flow history and thermal history. An apparent activation energy of 189 ± 5 kJ/mol for thermal degradation was found by modeling variations in the rate with temperature using an Arrhenius law model. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 66–74, 2005
High modulus polypropylene fibers. I. Mechanical properties
Authors: Gregor‐Svetec Diana , Sluga Franci
Published: July 2005

Extensive studies concerning the spinning and drawing of polypropylene resulted in a method for production of high modulus fibers under industrially feasible conditions. The fibers were produced in a conventional melt spinning and drawing process that was optimized in order to increase the elastic modulus of fibers. By such optimization of the process, a tensile strength of around 8 cN/dtex, an elastic modulus up to 14.7 GPa, and a dynamic modulus up to 19 GPa were attained. In this study the mechanical properties of polypropylene fibers were investigated, which were spun from fiber grade controlled rheology (CR) polymers and from the blends of a fiber grade CR polymer with a molding grade polymer in the composition range of 10–50 wt %. The addition of the molding grade polymer to the fiber grade CR polymer resulted in lower tensile strength and moduli, with one exception. By blending a CR polymer with 10% of the molding grade polymer, maximization of the elastic and dynamic modulus was achieved. The predicted modulus of a two‐phase blend, calculated from several representative equations, was compared with the elastic modulus of drawn fibers, determined from the specific stress versus strain curve, and the dynamic modulus, obtained from the sound velocity measurements. The best fit was achieved with the Kleiner simplex equation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1–8, 2005
Synthesis and characterization of 2‐diethyl‐aminoethyl–dextran–methyl methacrylate graft copolymer for nonviral gene delivery vector
Authors: Onishi Yasuhiko , Eshita Yuki , Murashita Aya , Mizuno Masaaki , Yoshida Jun
Published: July 2005

A stable and soapless latex of 2‐diethyl‐aminoethyl (DEAE)–dextran–methyl methacrylate (MMA) graft copolymer (DDMC) was developed for nonviral gene delivery vectors (complex between polycation and nucleic acid). DDMC was newly prepared using MMA and DEAE–dextran. Following a transfection protocol, transfection of HEK 293 cells by DDC1, DDC2, and DDC3 samples was carried out using plasmid DNA. With the transfection efficiency determined using the X‐Gal staining method, a higher value of 5 times or more was confirmed for DDMC samples DDC1 and DDC2 (but not for DDC3) than for the starting DEAE–dextran hydrochloride. The absorption spectrum shift at around 3400 cm−1 of the complexes between DDMC and DNA may support the formation of more compact structures by a Coulomb force between the phosphoric acid of DNA and the DEAE group of DEAE–dextran, concluding in DNA condensation. The specifically designed molecular structure of DDMC to ensure easy entry of DNA into cells needs not only a positive charge and a hydrophilic–hydrophobic microseparated domain but also more compact structures for transfection steps. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 9–14, 2005
Preparation of polystyrene/montmorillonite nanocomposites in supercritical carbon dioxide
Authors: Yan Chong , Ma Li , Yang Jichu
Published: July 2005

The preparation of polystyrene (PS)/montmorillonite (MMT) composites in supercritical carbon dioxide (SCCO2) was studied. Lipophilic organically modified MMT can be produced through an ion‐exchange reaction between native hydrophilic MMT and an intercalating agent (alkyl ammonium). PS/clay composites were prepared by free‐radical precipitation polymerization of styrene containing dispersed clay. X‐ray diffraction and transmission electron microscopy indicated that intercalation of MMT was achieved. PS/clay composites have a higher thermal decomposition temperature and lower glass‐transition temperature than pure PS. The IR spectrum analysis showed that the solvent of SCCO2 did not change the structures of the PS molecules, but there were some chemical interactions between the PS and the clay in the composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 22–28, 2005
Preparation and electro‐optical behaviors of polymer stabilized liquid crystal cells with chiral matrices derived from (−)‐camphor
Authors: Liu Jui‐Hsiang , Hung Hsien‐Jung , Wu Dung‐Shin , Hong Shou‐Mau , Fu Andy Y. G.
Published: July 2005

Novel chiral monomers derived from (−)‐camphor and difunctional monomers with biphenyl segments were synthesized. The molecular structures were identified using FTIR, NMR, and elemental analyses. Surface pretreated polymer stabilized cholesteric texture (PSCT) cells with various chiral nematic components were prepared. According to theory, they are kind of reversed mode PSCT cells. The helical twisting power (HTP) and pitches of the PSCT cells were evaluated. The polarized optical microscopic (POM) textures and the dependence of the optical properties on the applied voltage of the PSCT cells were investigated. The reflection band of the PSCT cells before and after UV irradiation were estimated. A blue shift of selective reflection of the PSCT cells was obtained after UV irradiation. PSCT cells with various reflecting colors and the dependence of the transmittance of the cells on applied voltage were investigated. Real image recording through a mask as well as the transmittance of PSCT cells controlled by applied voltage were also confirmed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 88–96, 2005
Follow‐up study of Wiedemann‐Rautenstrauch syndrome: Long‐term survival and comparison with Rautenstrauch's patient “G”
Authors: Arboleda Humberto , Arboleda Gonzalo
Published: July 2005

BACKGROUND

Wiedemann‐Rautenstrauch syndrome (WRS) characterizes a neonatal progeroid entity. In the last 30 years, 28 cases have been reported. In most cases of WRS, survival is short and long‐term studies are impossible.

CASE

In the present report, we describe a patient with WRS followed for 17 years at the Instituto de Genética, Universidad Nacional de Colombia; this is an exceptional survival period for a person with WRS. The information collected through 17 years for the present patient provides new knowledge about the natural evolution of this syndrome. New clinical and laboratory characteristics are compared with those reported for Rautenstrauch's patient “G.”

CONCLUSIONS

Our results confirm the variability of this syndrome, especially at the neurological level. However, many etiological and pathological aspects of this syndrome remain unknown. Birth Defects Research (Part A), 2005. © 2005 Wiley‐Liss, Inc.
Epidemiology of noncomplex left ventricular outflow tract obstruction malformations (aortic valve stenosis, coarctation of the aorta, hypoplastic left heart syndrome) in Texas, 1999–2001
Authors: McBride Kim L. , Marengo Lisa , Canfield Mark , Langlois Peter , Fixler David , Belmont John W.
Published: July 2005

BACKGROUND

The left ventricular outflow tract (LVOT) malformations aortic valve stenosis (AVS), coarctation of the aorta (CoA), and hypoplastic left heart syndrome (HLHS) contribute significantly to infant mortality due to birth defects. Previous epidemiology data showed rate differences between male and female and white and black ethnic groups. The Texas Birth Defects Registry, an active surveillance program, enables study in a large, diverse population including Hispanics.

METHODS

Records of children up to 1 year old with AVS, CoA, and HLHS born in Texas from 1999 to 2001, were collected from the registry. Those including additional heart defects or a chromosomal anomaly were excluded. Multivariate analysis included: infant sex; United States–Mexico border county residence; and maternal age, race/ethnicity, birthplace, and education.

RESULTS

There were 910 cases among 1.08 million live births, of which 499 met inclusion criteria. Multivariate modeling of all LVOT malformations combined demonstrated lower prevalence rate ratios (PRRs) for black males (0.26) and Hispanic males (0.70). Similar results were found for CoA but not AVS or HLHS. Higher PRRs were noted for increased maternal age for LVOT (1.3 for 24–34 years; 1.7 for >34 years), AVS, and HLHS, but not CoA, and higher PRRs across all diagnoses for males (LVOT PRR, 2.4) were noted. CoA PRRs were higher in border county vs. non–border county residents (PRR, 2.1). Maternal education and birthplace were not significant factors.

CONCLUSIONS

There are rate differences for males among all 3 ethnic groups. Sex and ethnic differences suggest genetic etiologies, where the ethnic differences could be used to find susceptibility loci with mapping by admixture linkage disequilibrium. Increased CoA rates along the U.S.–Mexico border suggest environmental causes that will require further monitoring. Birth Defects Research (Part A), 2005. © 2005 Wiley‐Liss, Inc.
Magnetic resonance imaging, computed tomography, and conventional X‐ray in 3 cases of symmelia
Authors: Dorenbeck Ulrich , Schreyer Andreas G. , Plendl Philipp J. , Hees Herbert , Feuerbach Stefan , Held Paul
Published: July 2005

BACKGROUND

Symmelia is a rare birth defect, often combined with severe malformations of the urogenital system and the lower gastrointestinal tract. Additionally, a deformed pelvis and various degrees of separation of the lower limbs are present.

CASES

We report the examination findings of 3 autopsy specimens of symmelia using magnetic resonance imaging (MRI) and computed tomography (CT) with 3‐dimensional (3D) reconstructions, and conventional X‐ray.

CONCLUSIONS

MRI and CT with the addition of 3D visualization can be used additionally with autopsy and conventional X‐ray images in the investigation of such complex anatomical abnormalities. Birth Defects Research (Part A), 2005. © 2005 Wiley‐Liss, Inc.
Transient Structural Ordering of the RNA‐Binding Domain of Carnation Mottle Virus p7 Movement Protein Modulates Nucleic Acid Binding
Authors: Vilar Marçal , Saurí Ana , Marcos Jose F. , Mingarro Ismael , Pérez‐Payá Enrique
Published: July 2005

Plant viral movement proteins bind to RNA and participate in the intra‐ and intercellular movement of the RNAs from plant viruses. However, the role and magnitude of the conformational changes associated with the formation of RNA–protein complexes are not yet defined. Here we describe studies on the relevance of a preexisting nascent α‐helix at the C terminus of the RNA‐binding domain of p7, a movement protein from carnation mottle virus, to RNA binding. Synthetic peptide analogues and single amino acid mutation at the RNA‐binding domain of recombinant p7 protein were used to correlate the transient structural order in aqueous solution with RNA‐binding potential.
How Does DNA Compaction Favor Chiral Selectivity with Cationic Species? Higher Selectivity with Lower Cationic Charge
Authors: Zinchenko Anatoly A. , Chen Ning , Murata Shizuaki , Yoshikawa Kenichi
Published: July 2005

A single‐molecule study on giant DNA compaction by enantiomeric dications and tetracations demonstrates that strong chiral discrimination in DNA compaction is manifested only if the positive charge on enantiomeric multications is relatively low. The increase in cationicity of the chiral compaction agent inevitably leads to an increase in nonspecific electrostatic interactions and quenching of chiral discrimination in the DNA‐folding phase transition.
Fluorescence‐Based Cloning of a Protein Tyrosine Kinase with a Yeast Tribrid System
Authors: Clark Daniel D. , Peterson Blake R.
Published: July 2005

Post‐translational modifications of proteins control myriad biological functions. However, relatively few methods exist for the identification of the enzymes that catalyze these modifications. To expand this repertoire, we report a yeast genetic approach that enables the identification of protein tyrosine kinases (PTKs) from cDNA libraries. Yeasts were transformed with four vectors encoding: 1) a potentially universal PTK substrate fused to the LexA DNA binding domain, 2) the Grb2‐SH2 domain fused to the B42 activation domain, 3) a fluorescent reporter gene controlled by LexA DNA sites, and 4) a Jurkat cDNA library. Transient expression of PTKs, such as the lymphocyte‐specific kinase Fyn, resulted in phosphorylation of the DNA‐bound substrate, recruitment of the Grb2‐SH2 domain, and activation of the fluorescent reporter gene. This brief induction of protein expression circumvented the potential toxicity of PTKs to the yeast. Fluorescence activated cell sorting (FACS) enabled isolation of PTKs, and these enzymes were further characterized by flow cytometry and immunoblotting. This approach provides a potentially general method for the identification and evaluation of enzymes involved in the post‐translational modification of proteins.
Drug‐eluting stents for coronary bifurcations: Bench testing of provisional side‐branch strategies
Authors: Ormiston John A. , Webster Mark W.I. , El Jack Seifeddin , Ruygrok Peter N. , Stewart James T. , Scott Douglas , Currie Erin , Panther Monique J. , Shaw Bronwyn , O'Shaughnessy Barbara
Published: July 2005

The objective of this study was to bench‐test provisional bifurcation stenting strategies to provide insights on how best to perform these with drug‐eluting stents (DESs). Bifurcation stenting with DESs reduces restenosis compared with bare metal stents (BMSs). Outcomes with a single DES are better than with two DESs but if the main branch is stented, there needs to be a reliable strategy for provisionally stenting the side‐branch with full ostial scaffolding and drug application. Stents were photographed in a phantom after deployment with different strategies. With provisional T‐stenting, placement of the side‐branch stent without gaps is difficult. The internal (or reverse) crush strategy fully scaffolds the side‐branch ostium but is experimental. The culotte technique providing excellent side‐branch ostial coverage is easier to perform with open‐cell or large‐cell stent design. In general, kissing balloon postdilatation improves stent expansion, especially at the ostium, and corrects distortion. However, a main‐branch kissing balloon of smaller diameter than the deploying balloon causes distortion. Final main‐branch postdilatation or sequential postdilatation prevents distortion after the internal crush strategy. © 2005 Wiley‐Liss, Inc.
Mechanistic Aspects of the Metal Catalyzed Alternating Copolymerization of Epoxides and Carbon Monoxide
Authors: Allmendinger Markus , Molnar Ferenc , Zintl Manuela , Luinstra Gerrit A. , Preishuber‐Pflügl Peter , Rieger Bernhard
Published: July 2005

The cobalt‐catalyzed alternating copolymerization of epoxides and CO is a novel, direct approach to aliphatic polyesters, such as poly(hydroxybutyrate) (PHB). This reaction was found to be catalyzed by Ph3Si[Co(CO)4] (4) and pyridine affording in a first step the stable mono‐insertion product Ph3Si‐O‐CH(CH3)‐CH2‐CO‐Co(CO)4 (5). However, a profound mechanistic understanding, especially of the role of pyridine as the key component for the polymerization reaction was missing. ATR‐IR online monitoring under catalytic conditions and DFT calculations were used to show that an acylpyridinium cation is formed by cleavage of the cobaltacyl bond of 5 in the presence of pyridine. The Lewis acid thus generated activates the next incoming epoxide monomer for ring opening through [Co(CO)4]−. The catalytic cycle is completed by a subsequent CO insertion in the new cobaltalkyl bond. The calculations are used to explore the energetic hypersurface of the polymerization reaction and are complemented by extended experimental investigations that also support the mechanistic hypotheses.
Biomimetic Hydrolysis of Penicillin G Catalyzed by Dinuclear Zinc(II) Complexes: Structure–Activity Correlations in β‐Lactamase Model Systems
Authors: Bauer‐Siebenlist Bernhard , Dechert Sebastian , Meyer Franc
Published: July 2005

A series of highly preorganized pyrazolate‐based dinuclear zinc complexes has been studied as functional synthetic analogues of metallo‐β‐lactamases, a class of bacterial enzymes that cause serious clinical problems because of their degradation of common β‐lactam antibiotics. We have investigated the hydrolytic cleavage of penicillin G mediated by the different dinuclear zinc complexes, and have deduced structure–activity correlations. While cooperative effects of the adjacent metal ions might be operative, these are found to either enhance or diminish β‐lactamase activity with respect to a single free zinc. Drastic differences in activity are ascribed to a lack of accessible binding sites after incorporation of the substrate within the bimetallic pocket of 2 and 4, whereas partial detachment of hemilabile ligand side arms in 1 and 3 opens up available coordination sites for nucleophile activation and/or for binding and polarisation of the β‐lactam amide oxygen atom. This interpretation has been corroborated by NMR spectroscopic and mass spectrometric evidence as well as by X‐ray crystallography of several adducts formed between the pyrazolate‐based dinuclear zinc scaffolds and the small substrate analogue oxazetidinylacetate (oaa), 5–7. In all adducts, the carboxylate group of oaa is the primary anchoring site and is nested in a bridging position within the bimetallic pocket. However, zinc binding of the β‐lactam amide oxygen atom has been confirmed crystallographically for the first time in 7, in which additional open‐site coordination sites are available.
Cyclohexane‐Based Low Molecular Weight Hydrogelators: A Chirality Investigation
Authors: Friggeri Arianna , van der Pol Cornelia , van Bommel Kjeld J. C. , Heeres André , Stuart Marc C. A. , Feringa Ben L. , van Esch Jan
Published: July 2005

Seven new 1,3,5‐cyclohexyltricarboxamide‐phenylalanine derivatives were synthesized in order to investigate the effect of the amino acid chirality on the gelating properties of these small molecules in water. Gelation tests have shown that enantiomerically pure homochiral 1,3,5‐cyclohexyltricarboxamide‐L‐phenylalanine is a non‐hydrogelator as it crystallizes from water, whereas the heterochiral derivatives with either two L‐phenylalanine moieties and one D‐phenylalanine (lld), or vice versa (ddl), are very good hydrogelators. Concentration‐dependent gel‐to‐sol transition‐temperature (Tgs) curves for lld or ddl gels show a sigmoidal behaviour, which is in contrast to the logarithmic curves generally observed for gels derived from low molecular weight gelators (LMWGs). Such sigmoidal behaviour can be related to interactions between fibre bundles, which give rise to intertwined bundles of fibres. Transmission electron microscopy (TEM) images of lld and ddl gels show a network of thin, unbranched, fibre bundles with diameters of 20 nm. Right‐handed twisted fibre bundles are present in the lld gel, whereas left‐handed structures can be found in the ddl gel. Each bundle of fibres consists of a finite number of primary fibres. Gels consisting of mixtures of gelators, lld and ddl, and nongelators (lll or ddd) were investigated by means of Tgs measurements, CD spectroscopy and TEM. Results show that the incorporation of nongelator molecules into gel fibres occurs; this leads to higher Tgs values and to changes in the helicity of the fibre bundles. Furthermore, it was found that peripheral functionalization of the homochiral derivatives lll or ddd by means of a second amino acid or a hydrophilic moiety can overcome the effect of chirality; this process in turn leads to good hydrogelators.
A New Protocol for the Consecutive α‐ and β‐Activation of Propiolates towards Electrophiles, Involving Conjugate Addition of Tertiary Amines and Intramolecular Silyl Migration
Authors: Matsuya Yuji , Hayashi Kousuke , Nemoto Hideo
Published: July 2005

Herein, we present a novel approach for the consecutive α‐ and β‐activation of conjugated alkynes and demonstrate the application of this methodology towards the CC bond‐forming reactions of propiolates. This new concept is based on the 1,4‐addition of a tertiary amine to a conjugated alkyne, followed by an aldol‐type addition to an aldehyde and subsequent intramolecular silyl migration. This sequential process is generally applicable for 3‐trimethylsilylpropiolates. The combination of methyl 3‐trimethylsilylpropiolate, 1,4‐diazobicyclo[2.2.2]octane (DABCO), and aromatic aldehydes brought about domino‐type CC bond formations to afford highly functionalized olefins as the major products. On the other hand, aliphatic aldehydes, including the sterically demanding aromatic aldehyde, 2,6‐dimethylbenzaldehyde, produced alkyne derivatives as the sole products from the reaction, presumably, by the reaction pathway common to the first cases. The intramolecular version of the reaction was successfully applied to the cyclization of trimethylsilylpropiolic esters derived from salicylaldehydes, leading to a new formylcoumarin synthesis. Studies of the reaction mechanisms are also described.
Intramolecular Carbolithiation of Allyl o‐Lithioaryl Ethers: A New Enantioselective Synthesis of Functionalized 2,3‐Dihydrobenzofurans
Authors: Barluenga José , Fañanás Francisco J. , Sanz Roberto , Marcos César
Published: July 2005

A new and easy method for the diastereoselective synthesis of 3‐functionalized 2,3‐dihydrobenzofuran derivatives from allyl 2‐bromoaryl ethers is described. The key step of this transformation involves an intramolecular carbolithiation reaction of allyl 2‐lithioaryl ethers. The substituents in both the allyl and the aryl moieties play an important and decisive role in stopping the reaction at the benzofuran thus avoiding a γ‐elimination reaction. Finally, this process is amenable to the synthesis of enantiomerically enriched compounds by using (−)‐sparteine as a chiral inductor.
Biocatalytic Approaches to Hetero‐Diels–Alder Adducts of Carbonyl Compounds
Authors: Gouverneur Véronique , Reiter Maud
Published: July 2005

Very little information is available on hetero‐Diels–Alderases for the assembly of heterocyclic products despite the synthetic value of these [4+2] cycloadditions. Hetero‐Diels–Alderase antibodies raised against a bicyclic transition state analogue have been generated for the cycloaddition of ethylglyoxylate with an all‐carbon diene. More recently, a conceptually novel biocatalytic approach to hetero‐Diels–Alder (HDA) adducts derived from carbonyl dienophiles has been developed mirroring a stepwise aldol Michael mechanism instead of a concerted pathway. In this approach, the two key steps are an antibody‐mediated kinetic resolution of β‐hydroxyenones and a subsequent ring‐closure process. An attractive feature of this methodology is the possibility to convert the enantioenriched aldol intermediates into tetrahydropyranones or dihydropyranones. This bioorganic route is best applied for the preparation of enantioenriched HDA adducts derived from poorly electrophilic acceptors, therefore complementing existing catalytic routes to these adducts based on the use of small organocatalysts or chiral Lewis acids.
Primary diagnosis of malignant mesothelioma by fine‐needle aspiration of a supraclavicular lymph node
Authors: Tafazzoli Alireza , Raza Anwar , Martin Sue Ellen
Published: July 2005

Malignant mesothelioma is a rare neoplasm with poor prognosis. The pleural form is defined as a malignant tumor of mesothelial cells with a diffuse growth pattern involving the visceral and parietal surfaces of the pleura. To our knowledge, there have only been two reported cases in the literature where fine‐needle aspiration (FNA) of a lymph node was the primary mode of diagnosis of malignant mesothelioma. We describe a 40‐yr‐old male in whom the primary diagnosis of malignant mesothelioma was made by FNA of a supraclavicular lymph node. The mesothelial origin of the tumor was confirmed with immunohistochemical studies. A pleural biopsy immediately preceding the FNA was interpreted as chronic inflammation. Most patients with clinically documented lymph node metastases of malignant mesothelioma have had a previously established diagnosis of mesothelioma. Our case demonstrates that FNA can be a simple and invaluable method of diagnosis in those unusual cases where diagnosis of malignant mesothelioma has not already been made before lymphadenopathy. Diagn. Cytopathol. 2005;33:122–125. © 2005 Wiley‐Liss, Inc.
Long‐term effects of muscle‐derived protein with molecular mass of 77 kDa (MDP77) on nerve regeneration
Authors: Itoh Soichiro , Fujimori Kazuhiro E. , Uyeda Atsuko , Matsuda Atsushi , Kobayashi Hisatoshi , Shinomiya Kenichi , Tanaka Junzo , Taguchi Takahisa
Published: July 2005

The long‐term effects of the 77‐kDa muscle‐derived protein (MDP77) on motor and sensory nerve regeneration were examined in vivo. Fourteen‐millimeter bridge grafts of the right sciatic nerve of SD rats were carried out with silicone tubes containing a solution of type I collagen together with 0, 5, 10, or 20 μg/ml recombinant human MDP77 (N = 10 in each group). Recovery of motor and sensory function was evaluated monthly by the maximal toe‐spread index (TSI) and hot‐plate test, respectively, for 6 months after the operation. Electrophysiology (nerve conduction velocity), histology (diameter and total number of the regenerated myelinated axons in the tube), and immunohistochemistry (total number of Schwann cells in the tube), as well as measurement of soleus muscle weight, were also performed at this time. Motor, but not sensory, function recovered rapidly in the MDP77‐treated groups in a dose‐dependent manner. Electrophysiological measurements and the ratio of soleus muscle weight corroborated the positive effects of MDP77 on motor nerve regeneration, but no facilitation of sensory nerve recovery was observed. Furthermore, histological and immunohistochemical evaluations suggested that MDP77 treatment accelerates Schwann cell migration, followed by enhanced maturation of regenerating axons, resulting in functional recovery of both the nerves and the atrophied, denervated muscle. © 2005 Wiley‐Liss, Inc.
UCHL‐1 gene in multiple system atrophy: A haplotype tagging approach
Authors: Healy Daniel G. , Abou‐Sleiman Patrick M. , Quinn Niall , Ahmadi Kourosh R. , Ozawa Tetsutaro , Kamm Christoph , Wullner Ullrich , Oertel Wolfgang H. , Burk Katrin , Dupont Erik , Pellecchia Maria T. , Tolosa Eduardo , Gasser Thomas , Holton Janice L. , Revesz Tamas , Goldstein David B. , Lees Andrew J. , Wood Nicholas W.
Published: July 2005

To date, the etiology of multiple system atrophy (MSA) has proved impenetrable. We investigated the role of genetic variation in the UCHL‐1 gene in MSA and looked for the presence of disease susceptibility alleles. We determined the linkage disequilibrium structure of the gene and employed a haplotype tagging strategy with power to represent 95% of the haplotype diversity. This approach was performed using a set of tagging single nucleotide polymorphisms (SNPs) that can infer the allelic state of all the common SNPs in UCHL‐1 with a high coefficient of determination. This strategy enabled us to scan across the gene and maintain the power to detect signal(s) from any potential functional variant(s). In 257 Gilman‐probable or ‐definite MSA subjects and 1,536 controls, we did not detect a case–control frequency difference for either the tagged haplotypes or for individual tagging SNPs. This search included the S18Y variant of UCHL‐1, which has been reported to be protective in Parkinson's disease. © 2005 Movement Disorder Society
Smokeless tobacco use and the risk of Parkinson's disease mortality
Authors: O'Reilly Eilis J. , McCullough Marji L. , Chao Ann , Jane Henley S. , Calle Eugenia E. , Thun Michael J. , Ascherio A.
Published: July 2005

We examined the association between smokeless tobacco use and Parkinson's disease (PD) mortality as assessed by death certificate in a prospective cohort of 95,981 never‐smoking men. In this cohort, smokeless tobacco use is inversely associated with PD mortality, with an age‐adjusted risk of 0.22 (0.07–0.67) among current users compared to never users. © 2005 Movement Disorder Society
Primary writing tremor: Report of a case successfully treated with botulinum toxin A injections and discussion of underlying mechanism
Authors: Singer Carlos , Papapetropoulos Spiridon , Spielholz Neil I.
Published: July 2005

Primary writing tremor (PWT) is a rare motor disorder of unknown etiology, where tremor is elicited primarily or exclusively with writing. We describe a patient with PWT, present a video before and after successful treatment with botulinum toxin type A injections, and discuss a possible underlying dystonic mechanism. © 2005 Movement Disorder Society
Sleep apnea syndrome in Parkinson's disease. A case–control study in 49 patients
Authors: Diederich Nico J. , Vaillant Michel , Leischen Mike , Mancuso Giovanna , Golinval Serge , Nati Romain , Schlesser Marc
Published: July 2005

In PD, the impact of nocturnal respiration on sleep continuity and architecture has not been systematically investigated by polysomnography (PSG). We performed a case–control study with retrospective analysis of PSG data of 49 PD patients. After classifying the PD patients according to their apnea/hypopnea index (AHI), they were matched with 49 controls in terms of age, gender, and AHI. There were 21 PD patients (43%) who had sleep apnea syndrome (SAS), classified as mild (AHI, 5–15) in 10 patients, moderate (AHI, >15–30) in 4 patients, and severe (AHI, > 30) in 7 patients. PD patients had more deep sleep (P = 0.02) and more nocturnal awakenings (P < 0.001) than the controls. Their body mass index (BMI) was lower (P = 0.04), and they maintained a more favorable respiratory profile, with higher mean and minimal oxygen saturation values (P = 0.006 and 0.01, respectively). These differences were preserved when only considering PD patients with AHI > 15. PD patients had less obstructive sleep apneas (P = 0.035), independently from the factor AHI. Only the respiratory changes of 4 PD patients with BMI > 27 and AHI > 15 (8%) approximated those seen in the controls. At an early or middle stage of the disease, non‐obese PD patients frequently have AHI values suggesting SAS, however, without the oxygen desaturation profile of SAS. Longitudinal studies of patients with such “abortive” SAS are warranted to establish if this finding reflects benign nocturnal respiratory muscle dyskinesia or constitutes a precursor sign of dysautonomia in PD. © 2005 Movement Disorder Society
Multiple lipomas, alcoholism, and neuropathy: Madelung's disease or MERRF?
Authors: Schoffer Kerrie , Grant Ian
Published: July 2005

We report a 51‐year‐old alcoholic man with a 10‐year history of cervical lipomas and progressive symmetrical sensory neuropathy, initially diagnosed with Madelung's disease, an idiopathic syndrome often attributed to chronic alcoholism. The eventual development of proximal weakness led to pathological and genetic testing which identified a A8344G mutation in the mitochondrial tRNA lysine gene, associated with MERRF (myoclonic epilepsy with ragged‐red fibers). This case demonstrates how the varied terminology for this syndrome has resulted in a lack of consistent recognition and assessment for mitochondrial cytopathy. Muscle Nerve, 2005
Reinnervation of laryngeal muscles: A study of changes in myosin heavy chain expression
Authors: Kingham Paul J. , Birchall Martin A. , Burt Rachel , Jones Alan , Terenghi Giorgio
Published: July 2005

Direct repair of the recurrent laryngeal nerve (RLN) results in synkinesis and compromised laryngeal function. We have therefore developed a pig model to investigate whether anastomosis of the phrenic nerve with the abductor branch of the RLN leads to specific reinnervation of abductor muscles. Expression of myosin heavy chain protein (MyHC), a marker of appropriate reinnervation, was determined in the posterior cricoarytenoid (PCA) abductor and thyroarytenoid (TA) adductor muscles following nerve injury and repair. The denervated PCA muscle exhibited decreased levels of the fast‐type MyHC isoforms IIA and IIB, and increased slow‐type MyHC expression. Similarly, there was a fall in type IIB levels in the denervated TA muscle but increases in both IIA and slow MyHC. Four months after repair, the MyHC expression in the PCA was near normal, suggesting that our model reduces the risk of synkinesis and ensures the accurate muscle reinnervation required for full functional recovery. Muscle Nerve, 2005
Health‐risk behaviours among adolescent survivors of childhood cancer
Authors: Bauld Catherine , Toumbourou J.W. , Anderson V. , Coffey C. , Olsson C.A.
Published: July 2005

Background

The purpose of the study was to investigate smoking, alcohol use, illicit drug use and sexual risk taking among adolescent survivors of childhood cancer treated in Australia.

Procedure

A comparison study selecting on exposure (cancer vs. healthy) and administering a branched computerised questionnaire assessing health‐risk behaviour, predominately by telephone interview. One hundred fifty‐three adolescent survivors of childhood cancer were compared with age matched healthy adolescents drawn from one of two Australian population based surveys of adolescent health. Behaviours assessed were tobacco use, alcohol use, binge drinking, cannabis use, pain reliever use, other illicit drug use and unprotected sex.

Results

Compared to their healthy peers, younger survivors (13‐ to 17‐years) were at an increased risk of reporting pain reliever use (OR = 2.1) for non‐medical purposes, but lower risk of binge drinking (OR = 0.20), cannabis use (OR = 0.25), other illicit drug use (OR = 0.31), tobacco use (OR = 0.38) and alcohol use (OR = 0.44). Older survivors (18‐ to 24‐years) were at an increased risk of reporting alcohol use (OR 1.5), but at lower risk of reporting cannabis use (OR = 0.27), other illicit drug use (OR = 0.44) and tobacco use (OR = 0.47). Survival analysis using the full adolescent survivor cohort (13‐ to 24‐years) showed that the age of onset of tobacco use was later for cancer survivors (hazard ratio HR = 0.65).

Conclusion

Adolescent cancer survivors show reduced involvement in most health‐risk behaviours, with the exception of pain reliever use among younger survivors and alcohol use among the older survivors. Although risks were reduced a substantial proportion of survivors engage in these behaviours. Pediatr Blood Cancer © 2005 Wiley‐Liss, Inc.
Antimetabolite‐based therapy in childhood T‐cell acute lymphoblastic leukemia: A report of POG study 9296
Authors: Winter Stuart S. , Holdsworth Mark T. , Devidas Meenakshi , Raisch Dennis W. , Chauvenet Allen , Ravindranath Yaddanapudi , Ducore Jonathan M. , Amylon Michael D.
Published: July 2005

Purpose

A previous Pediatric Oncology Group (POG) study showed high incidence of secondary acute myelogenous leukemia (AML) in children treated for T‐cell acute lymphoblastic leukemia (T‐ALL) or higher‐stage lymphoblastic lymphoma. To prevent secondary neoplasms, induce prolonged asparagine depletion, and maintain high event‐free survival (EFS) in children with newly diagnosed T‐ALL or higher‐stage non‐Hodgkins lymphoma (NHL), we designed this pilot study to determine feasibility and safety of substituting methotrexate/mercaptopurine for teniposide/cytarabine and PEG‐asparaginase for native asparaginase.

Patients and methods

Forty‐five patients were entered, 29 with T‐ALL and 16 with higher‐stage NHL. Forty‐two of 45 patients achieved complete remission (CR), and 27 completed the therapy in continuous CR. Treatment consisted of 4‐week induction then 6 weeks consolidation and ten 9‐week maintenance cycles. Therapy primarily comprised antimetabolites, anthracyclines, alkylating agents, and asparaginase. Expected chemotherapy duration was 100 weeks.

Results

Forty‐two of 45 patients achieved CR, and 27 completed therapy. The most common toxicities were Grade 3 or 4 myelosuppression after cyclophosphamide/cytarabine and allergic reactions to asparaginase. Two died of sepsis early in maintenance. Five‐year EFS was 68.5% (SE 9.1%) for T‐ALL and 81.3% (SE 9.8%) for NHL. Five‐year EFS was 73.1% (SE 6.8%) for the entire cohort. No patients treated entirely on this study developed secondary neoplasms. One patient taken off study for asparaginase toxicity was treated with multiagent therapy that contained teniposide, and died from secondary myelodysplasia (sMDS)/AML.

Conclusion

Substituting methotrexate/mercaptopurine for teniposide/cytarabine and PEG‐asparaginase for native asparaginase in a dose‐intensive regimen was feasible in children and young adults with newly diagnosed T‐ALL or higher‐stage NHL. EFS was not compromised and secondary neoplasms were decreased. © 2005 Wiley‐Liss, Inc.
Treatment of a clinically determined lower‐risk stage III non‐lymphoblastic non‐hodgkin lymphoma with less intensive therapy does not impact negatively on outcome
Authors: Belgaumi Asim F. , Shalaby Lobna , Al‐Kofide Amani , Chaudhary M. Ashraf , Alviedo Christopher , Sabbah Rajeh
Published: July 2005

Stage III NHL was divided into lower‐risk (LR) or high‐risk (HR) groups. Results of treatment were retrospectively reviewed for patients between 1993 through 2000. An intensive multiagent protocol was used for IIIHR, and a CHOP‐based, milder treatment for IIILR. Most LR therapy was outpatient, while treatment for HR patients was primarily inpatient. Five year EFS and OS for HR (n = 29) and LR (n = 23) groups was 86.2% and 95.6% (P = 0.26), and 93.1% and 100%, respectively (P = 0.4). LR had less toxicity. While these results need prospective confirmation, the data shows that less intensive therapy of a LR group of stage III NHL may not impact negatively on outcome. Pediatr Blood Cancer © 2005 Wiley‐Liss, Inc.
Potential clinical impact of taking multiple blood samples for research studies in paediatric oncology: How much do we really know?
Authors: Cole Michael , Boddy Alan V. , Kearns Pamela , Teh Kok H. , Price Lisa , Parry Annie , Pearson Andrew D.J. , Veal Gareth J.
Published: July 2005

Pharmacological studies of anti‐cancer agents in children are essential to determine their clinical safety and efficacy, both of which can differ considerably from that observed in adults. However, the potential clinical impact of taking blood samples, in addition to those required for standard clinical practice is commonly a concern for both medical and allied staff and parents. Frequently quoted ‘safe limits’ of 3%–5% of total blood volume taken on any one study day are not based on published data and may not be acceptable for all patients. This article reviews some of the reasons why clinical pharmacology data for anti‐cancer drugs is often lacking in a paediatric patient population, summarises data from a retrospective study investigating the potential impact of repeated blood sampling for research purposes and discusses how this issue may be more systematically addressed in future studies. Research involving children with cancer should be limited to those studies addressing key scientific questions and should be designed to limit both the number and volume of blood samples required. © 2005 Wiley‐Liss, Inc.
Thymic carcinoma in children
Authors: Yaris Nilgün , Nas Yunus , Cobanoglu Umit , Yavuz Melek N.
Published: July 2005

Thymic epithelial neoplasms consist of thymomas, thymic carcinoids, and thymic carcinomas. Carcinomas are malignant tumors of the thymus characterized by obvious cytological anaplasia. They constitute only 4%–14% of thymic epithelial neoplams. Thymic carcinoma rarely occurs in children. Research in the English literature carried out for the present study revealed only 14 cases younger than 18 years‐of‐age. Here we have reported a 16‐year old girl who presented with respiratory distress due to huge anterior mediastinal mass. Histological and immunohistochemical studies confirmed lymphoepithelioma‐like thymic carcinoma. She received systemic chemotherapy and radiotherapy. However, she died within 15 months due to progressive disease. © 2005 Wiley‐Liss, Inc.
Severe malignancy‐associated hypercalcemia in dysgerminoma
Authors: Matthew Richardson , Christopher Otis , Philippa Sprinz
Published: July 2005

Hypercalcemia is a rare complication of pediatric malignant germ cell tumors. The problem may be missed because of unawareness among pediatric oncologists. We describe a 16‐year‐old girl with an ovarian dysgerminoma associated with severe hypercalcemia, a metabolic abnormality infrequently reported with this disease. We review some of the potential causes of malignancy‐associated hypercalcemia and current treatment strategies. It is our recommendation that calcium levels should be monitored in all children with solid ovarian masses. Hypercalcemia seen in these situations may not improve until the tumor is removed. Pediatr Blood Cancer 2006; 47:621–623. © 2005 Wiley‐Liss, Inc.