bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and swelling behavior of thermosensitive poly(N‐isopropyl acrylamide‐co‐sodium‐2‐acrylamido‐2‐methyl propane sulfonate) and poly(N‐isopropyl acrylamide‐co‐sodium‐2‐acrylamido‐2‐methyl propane sulfonate‐co‐glycidyl methacrylate) hydrogels
Authors: Emik Serkan , Gürdağ Gülten
Published: January 2006

The crosslinked copolymers and terpolymers of N‐isopropyl acrylamide (NIPAm) with sodium‐2‐acrylamido‐2‐methyl propane sulfonate (NaAMPS) and glycidyl methacrylate (GMA) were prepared in the presence of N,N′‐methylene bisacrylamide (NMBA) as crosslinker by free radical solution polymerization at 4°C. Potassium persulfate (KPS) and potassium bisulfide (KBS) were used as initiator and accelerator, respectively. While molar percentages of NaAMPS in copolymers feed were varied as 1, 2, and 3; NaAMPS and GMA were used in the molar percentages of 1 : 1, 2 : 2, and 3 : 3, respectively, for the terpolymer preparation. NMBA contents were kept constant as 1 or 1.5 mol % of total monomer moles in feed composition. The effects of the comonomer type, feed composition, and the crosslinker contents on the lower critical solution temperatures (LCST), equilibrium swelling values (Q) of polymers, swelling kinetics in water at room temperature, and deswelling kinetics at 55°C were investigated. The results indicated that the higher the NaAMPS content in NIPAm/NaAMPS copolymer, the higher the Q and water uptake rate, but less the water release rate. However, the presence of hydrophobic GMA comonomer in the terpolymer of NIPAm/NaAMPS/GMA decreased the Q values, it increased both the water uptake and the water release rates. It was also observed that NIPAm/NaAMPS and NIPAm/NaAMPS/GMA polymers exhibit continuous phase transition behavior between 40 and 50°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 428–438, 2006
Electrical properties of conventional polyimide films: Effects of chemical structure and water uptake
Authors: Deligöz H. , Yalcinyuva T. , Özgümüs S. , Yildirim S.
Published: January 2006

A series of conventional polyimide (CPI) films, based on pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylicdianhydride (BTDA), were prepared by a two step process, and their dielectrical constant, dielectrical loss, and DC conduction behaviors were studied at different frequencies and voltages. Their dielectrical breakdown voltage, water uptake, and solubility properties were also investigated. The effects of chemical structure and water uptake on the electrical properties of the films are discussed in detail. The dielectric constants of the CPI films vary between 2.93 and 3.72 at 1 MHz frequency and they are in the following decreasing order: BTDA‐DDS > BTDA‐DDE > PMDA‐DDS > PMDA‐DDE. The structure and thermal and oxidative stability of films were analyzed by FTIR‐ATR and TGA, respectively. The results showed that all CPI films have good insulating properties, such as high dielectric breakdown voltage, low dielectric constant with stability for long period of frequency, and low leakage density. Our results concerning electrical properties also suggest that electron hopping is responsible for AC conduction and Poole‐Frenkel mechanism is predominant for DC conduction of all CPI films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 810–818, 2006
Biodegradable polymer made of styrene and N‐benzyl‐4‐vinylpyridinium chloride
Authors: Kawabata Nariyoshi , Kakimoto Chizuko , Ikeuchi Hisaya
Published: January 2006

A copolymer of styrene with N‐benzyl‐4‐vinylpyridinium chloride (BVP), poly(styrene‐co‐N‐benzyl‐4‐vinylpyridinium chloride) (PST‐co‐BVP), was degradable by activated sludge in soil when the oligo‐styrene portion was sufficiently small. The degradation of the equimolar copolymer followed first‐order kinetics when the polymer sample was 1.0 or 0.5 g/kg and gave a half‐life of 5.6 days. The degradation of PST‐co‐BVP with a reduced BVP content did not follow first‐order kinetics under the aforementioned conditions but appeared to follow the kinetics when the amount of the polymer sample was sufficiently small. Under the ultimate conditions, the half‐life of PST‐co‐BVP that contained 10.6 mol % BVP was estimated to be 12.5 days, and the half‐life of PST‐co‐BVP that contained 5 mol % BVP was expected to be 30–40 days. The incorporation of 5 mol % BVP appeared sufficient for making PST‐co‐BVP substantially biodegradable if we did not expect exceptionally rapid degradation. PST‐co‐BVP was different from conventional polystyrene but possessed biodegradability. Random scission of the main chain much predominated over uniform scission from the end of the polymer chain in the biodegradation of PST‐co‐BVP. The cleavage of the main chain at BVP appeared predominant over that of oligo‐styrene. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 554–559. 2006
Supercritical CO2‐assisted synthesis of polystyrene/clay nanocomposites via in situ intercalative polymerization
Authors: Li Jianbo , Xu Qun , Peng Qi , Pang Maizhi , He Suqin , Zhu Chengshen
Published: January 2006

Cyclodextrins can form inclusion complexes with different molecules with the aid of their special chemical (molecular) structures. Physical and chemical properties of molecules can change after the formation of complex. This special feature enables the usage of dextrins in different industry areas. In this study, applicability of cylcodextrins in textile dyeing and washing processes was investigated. With this aim, β‐cyclodextrin was used in direct dyeing of cellulosic fabrics and in rinsing processes of direct dyed fabrics. Retarder/leveling effect of β‐cyclodextrin in dyeing process has been studied and the results were compared with that of a commercial product. In general, cyclodextrins were used in washing processes to remove the absorbed surfactants. It has been investigated whether this effect was the same for washing of dyed fabrics. Eight different direct dyes, for which the chemical structures are known, were used in dyeing and washing processes, and effect of β‐cyclodextrin on different chemical structures was investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 208–218, 2006
Effects of reaction and cure temperatures on morphology and properties of poly(ester‐urethane)
Authors: Zeng Ming , Zhang Lina
Published: January 2006

Poly(ester‐urethane) was synthesized from poly(ethylene glycol adipate) (PEG) and 2,4‐toluene diisocyanate (TDI) to study the effects of reaction temperature and cure temperature on the crystallization behavior, morphology, and mechanical properties of the semicrystalline polyurethane (PU). PEG as soft segment was first reacted with TDI as hard segment at 90, 100, and 110°C, respectively, to obtain three kinds of PU prepolymers, coded as PEPU‐90, PEPU‐100, and PEPU‐110. Then the PU prepolymers were crosslinked by 1,1,1‐tris (hydroxylmethyl) propane (TMP) and were cured at 18, 25, 40, 60, and 80°C. Their structure and properties were characterized by attenuated total reflection Fourier transform infrared, wide‐angle X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis, and tensile testing. With an increase of the reaction temperature from 90 to 100°C, the crystallinity degree of soft segment decreased, but interaction between soft and hard segments enhanced, leading to the increase of the glass transition temperature (Tg) of soft domain and tensile strength. When the cure temperature was above 60°C, miscibility between soft and hard segments of the PEPU films was improved, resulting in relatively low crystallinity and elongation at break, but high soft segment Tg and tensile strength. On the whole, all of the PEPU‐90, PEPU‐100, and PEPU‐110 films cured above 60°C possessed higher tensile strength and elongation at break than that of the films cured at other temperatures. The results revealed that the reaction temperature and cure temperature play an important role in the improvement of the crosslinking structure and mechanical properties of the semicrystalline PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 708–714, 2006
Hydroxyalkylation of 6‐aminouracil
Authors: Chmiel‐Szukiewicz Elżbieta
Published: January 2006

Reactions of 6‐aminouracil with formaldehyde, ethylene and propylene oxide, and ethylene carbonate were studied. Hydroxyalkyl derivatives of 6‐aminouracil were prepared. The structure of the products were established by elemental analysis, 1H‐NMR, and IR techniques. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 715–719, 2006
Long‐term changes in the fish assemblage of the Laja River, Guanajuato, central Mexico
Authors: Mercado‐Silva Norman , Lyons John , Díaz‐Pardo Edmundo , Gutiérrez‐Hernández Altagracia , Ornelas‐García Claudia Patricia , Pedraza‐Lara Carlos , Zanden M. Jake Vander
Published: January 2006

The structure and composition of fish communities in rivers of central Mexico have been altered as a result of water over‐exploitation, habitat fragmentation, introduction of exotic species, and pollution. However, the specific pattern and degree of change are poorly documented.

Long‐term information from the Laja River (Guanajuato, Mexico) in the Lerma River basin was used to explore trends in fish species richness and community composition (species origin, trophic niche, tolerance, and preferred habitat) from the 1960s to the present in both river and reservoir sites.

Declines in native, sensitive, benthic native and carnivore species ranging from 11% to 30% per decade, and increases in the number of tolerant and exotic species by 9–20% per decade, are documented. Repeated measures ANOVA and sign tests revealed significant declines in the number of benthic, native, carnivore and sensitive species. Species richness, number of exotics, tolerant species and omnivore species did not change statistically, though statistical power was low. Some important changes occurred in these variables, such as the expansion and establishment of exotics such as Xiphophorus variatus and Micropterus salmoides, which pose a serious potential threat to native species.

The changes in fish community composition for the Laja portray how the fish communities in other rivers in central Mexico, for which long‐term data do not exist, have changed or could change if environmental deterioration continues.

Copyright © 2006 John Wiley & Sons, Ltd.
Laser‐scanning lithography (LSL) for the soft lithographic patterning of cell‐adhesive self‐assembled monolayers
Authors: Miller Jordan S. , Béthencourt Mathilde I. , Hahn Mariah , Lee T. Randall , West Jennifer L.
Published: January 2006

We report the development of laser‐scanning lithography (LSL), which employs a laser‐scanning confocal microscope to pattern photoresists that can be utilized, for example, in the fabrication of masters for use in soft lithography. This convenient technique provides even exposure across the entire view field and facilitates accurate alignment of successive photoresist exposures. Features on the scale of 3 µm have been achieved to date with a 10× objective (NA 0.45). Virtual masks, instructions for laser irradiation, were drawn using the Region of Interest (ROI) function of a Zeiss LSM 510 microscope. These regions were then exposed to a 458 nm argon laser for 32 µs (0.9 mW/µm2). Differential interference contrast (DIC) imaging was utilized with a non‐destructive 514 nm argon laser as an immediate quality check of each exposure, to align successive exposures, and to reduce chromatic aberration between imaging and exposure. Developed masters were replica‐molded with poly(dimethylsiloxane) (PDMS); these masters were then utilized for microcontact printing of cell‐adhesive self‐assembled monolayers (SAMs) to demonstrate the utility of this process. Initial studies confirmed that human dermal fibroblast adhesion and spreading were limited to cell‐adhesive SAM areas. LSL is a rapid, flexible, and readily available technique that will accelerate master design and preparation; moreover, it can be applied to additional forms of photolithography and photopolymerization for studies in cell biology, biomaterials design and evaluation, materials science, and surface chemistry. © 2006 Wiley Periodicals, Inc.
Altering the Regioselectivity of Cytochrome P450 CYP102A3 of Bacillus subtilis by Using a New Versatile Assay System
Authors: Lentz Oliver , Feenstra Anton , Habicher Tilo , Hauer Bernhard , Schmid Rolf D. , Urlacher Vlada B.
Published: January 2006

A novel monooxygenase (CYP102A3) has been discovered within the Bacillus subtilis genome that reveals a similarity of 76 % to the well‐known cytochrome P450 BM‐3 of B. megaterium (CYP102A1). Both enzymes are natural fusion proteins consisting of a heme domain and a FAD/FMN‐reductase domain. Because of their high turnover rates, these biocatalysts are of special interest for industrial applications, but show only limited regioselectivity. In this work, the regioselectivity of CYP102A3 was changed by directed evolution and protein design to hydroxylate substrates not only in different subterminal, but also to a high extent, in terminal carbon chain positions. To enable a high‐throughput screening procedure, a very versatile assay was developed that is capable of discriminating between terminal and subterminal hydroxylation of carbon chains. A double mutant of CYP102A3 was obtained that produces 48 % octan‐1‐ol as the main product of the reaction.
Production of Lewis x Tetrasaccharides by Metabolically Engineered Escherichia coli
Authors: Dumon Claire , Bosso Claude , Utille Jean Pierre , Heyraud Alain , Samain Eric
Published: January 2006

Two tetrasaccharides carrying the trisaccharidic Lewis x motif on a GlcNAc or a Gal residue were produced on the gram‐scale by high‐cell‐density cultures of metabolically engineered Escherichia coli strains that overexpressed the Helicobacter pylori futA gene for α‐3 fucosyltransferase and the Neisseria meningitidis lgtB gene for β‐4 galactosyltransferase. The first compound Galβ‐4(Fucα‐3)GlcNAcβ‐4GlcNAc was produced by glycosylation of chitinbiose, which was endogenously generated in the bacterial cytoplasm by the successive action of the rhizobial chitin‐synthase NodC and the Bacillus circulans chitinase A1, whose genes were additionally expressed in the E. coli strain. The second compound, Galβ‐4(Fucα‐3)GlcNAcβ‐3Gal, was produced from exogenously added Gal by a strain that was deficient in galactokinase activity and overexpressed the additional N. meningitidis lgtA gene for β‐3 N‐acetylglucosaminyltransferase.
Genetic Targeting of Individual Cells with a Voltage‐Sensitive Dye through Enzymatic Activation of Membrane Binding
Authors: Hinner Marlon J. , Hübener Gerd , Fromherz Peter
Published: January 2006

Optical recording of the electrical activity of individual neurons in culture or in a tissue requires cell‐selective staining with a fluorescent voltage‐sensitive dye. In a proof‐of‐principle experiment, we implement a novel approach to genetically targeted staining. The method relies on a water‐soluble precursor dye and an overexpressed cell‐surface enzyme that transforms the precursor into a hydrophobic dye that binds to the targeted cell. We fused an alkaline phosphatase to a specifically designed general‐purpose membrane anchor, and the fusion protein was expressed on the surface of HEK293 cells, as was corroborated by immuno‐ and histochemical staining. We next synthesised an amphiphilic hemicyanine dye containing two enzymatically cleavable phosphate groups at its hydrocarbon tails. When the phosphate groups were removed, the binding to membranes was enhanced by a factor of a thousand, as shown by titration with lipid vesicles. We observed selective staining of enzymatically active cells by fluorescence microscopy in a mixed population of phosphatase‐transfected and untransfected HEK293 cells. The critical parameters of enzyme‐induced cell‐selective staining were elucidated by a simple kinetic model to guide further developments of the method.
Fluorine Segregation in Crystalline Materials: Structural Control and Solid‐State [2+2] Cycloaddition in CF3‐Substituted Tetrathiafulvalene Derivatives
Authors: Jeannin Olivier , Fourmigué Marc
Published: January 2006

The well‐known influence of long perfluorinated chains on the structures and stability of amphiphilic molecules in liquid crystalline mesophases or mesoscopic micellar arrangements is evaluated here in the realm of crystalline materials based on rigid aromatic molecules bearing only a limited number of CF3moieties. Tetrathiafulvalene (TTF) derivatives bearing one or two CF3groups, that is, (Z)‐ and (E)‐(CF3)2TTF ((Z)‐1, (E)‐1), EDT‐TTF‐CF3(2), and EDT‐TTF(CF3)2(3) (EDT=ethylenedithio) are prepared from the 1,3‐dipolar reaction of methyl 4,4,4‐trifluorotetrolate with ethylenetrithiocarbonate. The structures of neutral (Z)‐1, (E)‐1,2,and3as indicated by single‐crystal X‐ray diffraction measurements reveal the recurrent formation of layered structures with a strong segregation of the fluorinated moieties and formation of fluorous bilayers, attributed to the amphiphilic character of those TTF derivatives upon CF3functionalization, and without need for longer CnF2n+1(n>1) perfluorinated chains. The short intermolecular distance between outer CC double bonds observed in the layered structure of (E)‐1allows a solid‐state [2+2] photocyclization with formation of chiral dyads incorporating the characteristic cyclobutane ring. These dyads containing two dihydrotetrathiafulvalene moieties facing each other exhibit reversible oxidation to the mixed‐valence radical cation state and organize in the solid‐state into the same layered structures with fluorous bilayers.
Catalytic Enantioselective Three‐Component Hetero‐[4+2] Cycloaddition/Allylboration Approach to α‐Hydroxyalkyl Pyrans: Scope, Limitations, and Mechanistic Proposal
Authors: Gao Xuri , Hall Dennis G. , Deligny Michael , Favre Annaick , Carreaux François , Carboni Bertrand
Published: January 2006

This article describes the design and optimization of a catalytic enantioselective three‐component hetero‐[4+2] cycloaddition/allylboration reaction between 3‐boronoacrolein, enol ethers, and aldehydes to afford α‐hydroxyalkyl dihydropyrans. The key substrate, 3‐boronoacrolein pinacolate (2) was found to be an exceptionally reactive heterodiene in the hetero‐[4+2] cycloaddition catalyzed by Jacobsen's chiral CrIII catalyst 1. The scope and limitations of this process were thoroughly examined. The adduct of 3‐boronoacrolein pinacolate and ethyl vinyl ether was obtained in high yield and with over 95 % enantioselectivity. This cyclic α‐chiral allylboronate adds to a very wide variety of aldehyde substrates, including unsaturated aldehydes and α‐chiral aldehydes to give diastereomerically pure products. Acyclic 2‐substituted enol ethers can be employed, in which case the catalyst promotes a kinetically selective reaction that favors Z enol ethers over the E isomers. Surprisingly, 3‐boronoacrolein pinacolate was found to be a superior heterodiene than ethyl (E)‐4‐oxobutenoate, and a mechanistic interpretation based on a possible [5+2] transition state is proposed.
Ruthenium‐Catalyzed Asymmetric Epoxidation of Olefins Using H2O2, Part I: Synthesis of New Chiral N,N,N‐Tridentate Pybox and Pyboxazine Ligands and Their Ruthenium Complexes
Authors: Tse Man Kin , Bhor Santosh , Klawonn Markus , Anilkumar Gopinathan , Jiao Haijun , Döbler Christian , Spannenberg Anke , Mägerlein Wolfgang , Hugl Herbert , Beller Matthias
Published: January 2006

The synthesis of chiral tridentate N,N,N‐pyridine‐2,6‐bisoxazolines 3 (pybox ligands) and N,N,N‐pyridine‐2,6‐bisoxazines 4 (pyboxazine ligands) is described in detail. These novel ligands constitute a useful toolbox for the application in asymmetric catalysis. Compounds 3 and 4 are conveniently prepared by cyclization of enantiomerically pure α‐ or β‐amino alcohols with dimethyl pyridine‐2,6‐dicarboximidate. The corresponding ruthenium complexes are efficient asymmetric epoxidation catalysts and have been prepared in good yield and fully characterized by spectroscopic means. Four of these ruthenium complexes have been characterized by X‐ray crystallography. For the first time the molecular structure of a pyboxazine complex {2,6‐bis‐[(4S)‐4‐phenyl‐5,6‐dihydro‐4H‐[1,3]oxazinyl]pyridine}(pyridine‐2,6‐dicarboxylate)ruthenium (S)‐2 aa, is presented.
Structurally Characterized Hetero‐Oligopolyphenylenes: Synthetic Advances Toward Next‐Generation Heterosuperbenzenes
Authors: Gregg Daniel J. , Ollagnier Cecile M. A. , Fitchett Christopher M. , Draper Sylvia M.
Published: January 2006

The successful Diels–Alder [2+4] cycloaddition1 of dipyrimidyl acetylene and suitably substituted 2,3,4,5‐tetraarylcyclopenta‐2,4‐dien‐1‐ones (3–7) generates a series of selectively functionalized hexaarylbenzenes. Each has two pairs of peripheral functional groups (R′ and R=tert‐butyl 8 and R=methyl 9, methoxy 10, bromo 11, triisopropylsilylethynyl 12) and four ortho‐imine nitrogen atoms. The dibromo derivative 11 is a useful precursor for the formation of a mono ethynyl 13 and diethynyl 14 substituted polyphenylene. Changing the dienophile to di(2‐thienyl)acetylene gives an S‐heteroatom polyphenylene 15. The compounds were fully characterized by using 1H, 13C and a range of 2 D NMR spectroscopic techniques, elemental analysis, and mass spectrometry. Oxidative cyclodehydrogenation of dimethoxy hexaphenylbenzene 10 by using iron(III) chloride results in the formation of a spirocyclic dienone 16, which in a separate reaction undergoes dienone/phenol rearrangement to give the first 4‐fused‐ring, N‐heterosuperbenzene (HSB) 17. Six single crystal molecular structures reveal the commonality of unidirectional twisting of the external aromatic rings in these heteroatom polyphenylenes. The twist angles and any H‐bonding or interdigitation in these structures are discussed.
Inhibition of human telomerase reverse transcriptase by nonsteroidal antiinflammatory drugs in colon carcinoma
Authors: He Hua , Xia Harry Hua‐Xiang , Wang Ji De , Gu Qing , Lin Marie C.M. , Zou Bing , Lam Shiu Kum , Chan Annie O.O. , Yuen Man Fung , Kung Hsiang Fu , Wong Benjamin Chun‐Yu
Published: January 2006

BACKGROUND

Telomerase activation, which is observed in most human cancers, plays an important role in carcinogenesis. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activity. The aim of the study was to investigate whether nonsteroidal antiinflammatory drugs (NSAIDs) inhibit telomerase activity and hTERT.

METHODS

Four colon carcinoma cell lines, HT‐29, COLO205, CRL‐2134, and SW1116, were used in the experiments. Polymerase chain reaction‐based telomeric repeat amplification (TRAP) enzyme‐linked immunosorbent assay (ELISA) was used to measure telomerase activity in the cells after treatment with aspirin, indomethacin, or SC‐236 (a specific cyclooxygenase‐2 [COX‐2] inhibitor). Expression of hTERT mRNA and protein was detected by reverse transcription–polymerase chain reaction (RT‐PCR) and Western blotting, respectively. The dual luciferase reporter assay was performed to identify the potential cis‐response elements to NSAIDs in the promoter region of hTERT.

RESULTS

Aspirin, indomethacin, and SC‐236 inhibited telomerase activity in HT‐29, COLO205, and CRL‐2134 cell lines, but not in the SW1116 cell line. NSAIDs inhibited hTERT mRNA and protein expression through suppression of hTERT transcriptional activity. The hTERT promoter fragment −145 to −330 basepairs (bp) upstream of the ATG starting site was sufficient to respond to the NSAID‐induced inhibitory effect and the inhibition was COX‐2‐independent.

CONCLUSION

NSAIDs inhibit telomerase activity at hTERT transcriptional, mRNA, and protein levels in colon carcinoma cells. The hTERT promoter fragment −145 to −330 bp may be the cis‐response element to NSAIDs. Cancer 2006. © 2006 American Cancer Society.
His239Arg SNP of HRAD9 is associated with lung adenocarcinoma
Authors: Maniwa Yoshimasa , Yoshimura Masahiro , Bermudez Vladimir P. , Okada Kenji , Kanomata Naoki , Ohbayashi Chiho , Nishimura Yoshihiro , Hayashi Yoshitake , Hurwitz Jerard , Okita Yutaka
Published: January 2006

BACKGROUND

It was previously reported that a functional human (h) Rad9 protein accumulated in the nuclei of nonsmall cell lung carcinoma (NSCLC) cells. Those experiments, however, did not examine whether the hRad9 gene was mutated in those cells. The sequence of the HRAD9 gene in NSCLC cells was investigated.

METHODS

The sequence of the HRAD9 was examined in tumor and peripheral normal lung tissues obtained from 50 lung adenocarcinoma patients during surgery. The expression of its mRNA using reverse transcription polymerase chain reaction (RT‐PCR) was also examined.

RESULTS

No sequence alterations were detected in the HRAD9 gene, which was found to be normally transcribed in surgically resected lung carcinoma cells. However, in eight (16.0%) cases a single nucleotide polymorphism (SNP) was observed at the second position of codon 239 (His/Arg heterozygous variant) of the gene. This frequency was significantly higher than that found in the normal population.

CONCLUSIONS

Whereas the capacity to produce a functional hRad9 protein was intact in lung adenocarcinoma cells, a nonsynonymous SNP of HRAD9 was detected that might be associated with the development of lung adenocarcinoma. Cancer 2006. © 2006 American Cancer Society.
Valproate enhances imatinib‐induced growth arrest and apoptosis in chronic myeloid leukemia cells
Authors: Morotti Alessandro , Cilloni Daniela , Messa Francesca , Arruga Francesca , Defilippi Ilaria , Carturan Sonia , Catalano Renata , Rosso Valentina , Chiarenza Annalisa , Pilatrino Chiara , Guerrasio Angelo , Taulli Riccardo , Bracco Enrico , Pautasso Marisa , Baraban Daniela , Gottardi Enrico , Saglio Giuseppe
Published: January 2006

BACKGROUND

The objective of this study was to evaluate the ability of the clinically available histone deacetylase (HDAC) inhibitor valproate to enhance the cytotoxicity of the Bcr‐Abl inhibitor imatinib in imatinib‐resistant cell lines.

METHODS

Interactions between imatinib, and valproate have been examined in imatinib‐sensitive and ‐resistant chronic myeloid leukemia (CML)cell lines (K562, KCL‐22, CML‐T1) and in bone marrow mononuclear cells (MNCs) derived from imatinib‐resistant CML patients.

RESULTS

In imatinib‐sensitive cell lines, cotreatment with imatinib 0.5 μM and valproate 5 μM for 48 hours potently enhanced imatinib‐induced growth arrest and apoptosis. In resistant cell lines and in primary MNCs derived from imatinib‐resistant patients, valproate restored sensitivity to the cytotoxic effects of imatinib. Coexposure of cells to valproate and imatinib was associated with repression of several genes involved in Bcr‐Abl transformation. In particular, the combination valproate–imatinib downregulated the expression of Bcr‐Abl and the antiapoptotic protein Bcl‐2, which is particularly overexpressed in imatinib‐resistant clones.

CONCLUSIONS

Data from this study suggested that administration of the clinically available HDAC inhibitor valproate may be a powerful strategy to enhance cytotoxic effects of imatinib in those patient resistant to imatinib or in which complete cytogenetic remission has been not reached. Cancer 2006. © 2006 American Cancer Society.
Comparative analysis of mRNA and protein expression of Popdc1 (Bves) during early development in the chick embryo†
Authors: Torlopp Angela , Breher Stephanie S. , Schlüter Jan , Brand Thomas
Published: January 2006

The isolation of the Popeye gene family was based on its preferential expression in striated muscle tissue. Recently, a monoclonal antibody against chick Popdc1 (also known as Bves) became available and was used in this study to comparatively analyze the expression pattern of Popdc1 at both the protein and mRNA level during early chick embryogenesis. Using whole‐mount immunohistochemistry, expression in the heart was first observed at Hamburger and Hamilton (HH) stage 10 in the presumptive left ventricular segment. Cardiac expression was confined to differentiated cardiac myocytes, and undifferentiated myocytes at the anterior and posterior pole showed little expression. After looping, the outer curvature myocardium showed prominent Popdc1 staining, whereas the inner curvature was unlabeled. Despite previous reports, Popdc1 protein was not detectable at any time point in the proepicardium, epicardium, or the smooth muscle layer of the coronary vessels. Whole‐mount in situ hybridization using a full‐length Popdc1 probe detected novel expression domains, which have not been described previously. Popdc1 mRNA was found in Hensen's node at HH stage 4, and by HH stage 5+, expression became asymmetric. In addition, Popdc1 mRNA was found in pharyngeal endoderm and in the notochordal plate. Subsequently, beginning at HH stage 9, Popdc1 mRNA expression was found in the cardiac mesoderm and expression was maintained in the heart in a pattern very similar to the one observed by antibody staining. Developmental Dynamics 235:691–700, 2006. © 2006 Wiley‐Liss, Inc.
Bves, a member of the Popeye domain‐containing gene family
Authors: Osler Megan E. , Smith Travis K. , Bader David M.
Published: January 2006

Bves was discovered through subtractive screens designed to identify heart‐enriched transcripts. Bves is a transmembrane protein that possesses a highly conserved structure among species of the animal kingdom. Various approaches have been used to elucidate the expression pattern of Bves mRNA and protein as well as its function in developing and mature organisms. Emerging evidence indicates that this protein is present in muscle and epithelia of developing embryos and the adult. In vitro functional studies predict a role in cell–cell interaction and/or adhesion. In vivo analysis of protein function is very limited at present, but recent work in Xenopus supports the importance of Bves in epithelial integrity. Presented in this review is a compilation of published findings concerning Bves gene and protein characteristics, expression patterns in embryos and cells, and functional significance as determined thus far. Presently, the literature supports a hypothesis that Bves is essential to the junctional architecture of muscle and epithelial cell types. Although there remain aspects of Bves structure, expression, and function that are not completely resolved, now is an appropriate time to summarize current knowledge about this protein, the remaining questions, and what its potential role in development might be. This review will serve as a departure point for others who become interested in the study of this highly conserved protein. Developmental Dynamics 235:586–593, 2006. © 2006 Wiley‐Liss, Inc.
Experimental hypoxia and embryonic angiogenesis†
Authors: Naňka O. , Valášek P. , Dvořáková M. , Grim M.
Published: January 2006

We examined the role of hypoxia and HIF factors in embryonic angiogenesis and correlated the degree of hypoxia with the level of HIF and VEGF expression and blood vessel formation. Quail eggs were incubated in normoxic and hypoxic (16% O2) conditions. Tissue hypoxia marker, pimonidazol hydrochloride, was applied in vivo for 1 hr and detected in sections with Hypoxyprobe‐1 Ab. VEGF and HIF expression was detected by in situ hybridization. HIF‐1α protein was detected in sections and by Western blot. Endothelial cells were visualized with QH‐1 antibody. Hypoxic regions were detected even in normoxic control embryos, mainly in brain, neural tube, branchial arches, limb primordia, and mesonephros. The expression patterns of HIF‐1α and HIF‐1β factors followed, in general, the Hypoxyprobe‐1 marked regions. HIF‐2α was predominantly expressed in endothelial cells. Diffuse VEGF expression was detected in hypoxic areas of neural tube, myocardium, digestive tube, and most prominently in mesonephros. Growing capillaries were directed to areas of VEGF positivity. Hypoxic regions in hypoxic embryos were larger and stained more intensely. VEGF and HIF‐1 factors were proportionately elevated in Hypoxyprobe‐1 marked regions without being expressed at new sites and were followed by increased angiogenesis. Our results demonstrate that normal embryonic vascular development involves the HIF‐VEGF regulatory cascade. Experimentally increasing the level of hypoxia to a moderate level resulted in over‐expression of HIF‐1 factors and VEGF followed by an increase in the density of developing vessels. These data indicate that embryonic angiogenesis is responsive to environmental oxygen tension and, therefore, is not entirely genetically controlled. Developmental Dynamics 235:723–733, 2006. © 2006 Wiley‐Liss, Inc.
Iodine Attack on the Metalloligand [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)]: Surprising Formation of the [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ Cation
Authors: García‐Castro María , Martín Avelino , Mena Miguel , Poblet Josep‐M. , Yélamos Carlos
Published: January 2006

The reactivity of the trinuclear imido‐nitrido complex [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)] (1) and derivatives thereof withiodine has been investigated. Treatment of the indium(I)adduct [IIn{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (2) with I2 (1 equiv.) in benzene afforded the indium(III) complex [I3In{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (3), but with excess of iodine the precipitation of orange crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][InI4] (4) takes place. Analogous treatment of the metalloligand 1 with I2 in toluene gave initially the iodine(I) derivative [I{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}][I3] (5). Surprisingly, toluene solutions of 5 at room temperature produced crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][I3]·C7H8 (6·C7H8). The trinuclear titanium cation [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ of complexes 4 and 6 has been structurally characterized by a combination of X‐ray and DFT studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Complexes of Bidentate Phosphane Selenide Ligands with Mesitylenetellurenyl Iodide and with Tellurium Diiodide
Authors: Hrib Cristian G. , Jones Peter G. , du Mont Wolf‐W. , Lippolis Vito , Devillanova Francesco A.
Published: January 2006

Bis(diphenylphosphanyl)methane diselenide (dppmSe2, 1) and bis(diphenylphosphanyl)ethane diselenide (dppeSe2, 2) reacted with 2 equiv. Br2 or I2 to form the insoluble solid products, dppm(SeX2)2 (X = Br, 3; X = I, 4) and dppe(SeX2)2 (X = Br, 5; X = I, 6). However, using the iodine‐like electrophile mesitylenetellurenyl iodide (MesTeI, 7), fairly soluble complexes, dppmSe2[Te(I)Mes]2 (8) and dppeSe2[Te(I)Mes]2 (9), were obtained. Complexes 8 and 9 contain two T‐shaped (10‐Te‐3) Se–Te(Mes)–I moieties bridged by dppm or dppe; solid 9 exhibits intermolecular soft–soft interactions between approximately linear Se–Te–I units. In a side reaction accompanying the crystallisation of complex 8, or by the reaction of 1 with Te and I2, a chelate complex dppmSe2TeI2 (10) was formed. Fortuitously, a crystal of the related compound dppeSe2TeI2 (11) was also obtained. In 10, a square planar cis‐Se2TeI2 group is part of a six‐membered ring, and 11 is a coordination polymer with trans‐Se2TeI2 moieties bridged by dppe. Averaged 31P‐ and 77Se NMR signals including 77Se–31P couplings, together with broad 125Te NMR singlets indicate phosphane selenide ligand exchange in solution, that is, the kinetically labile behaviour of complexes 8 and 9. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
TheAlpher, Bethe, Gamowof isoelectric focusing, the alpha‐Centaury of electrokinetic methodologies. Part I
Authors: Righetti Pier Giorgio
Published: January 2006

The birth and evolution of IEF in conventional carrier ampholyte buffers is reviewed here, from a shaky start during World War II,viadesperate attempts of Svensson to create pH gradients by stationary electrolysis of salts, to the development of the IEF theory and the solution of the steady‐state equation. The remarkable synthetic process of Ampholines, as ingeniously devised by Vesterberg, is additionally recalled, with a thorough description of the fundamental properties of these amphoteric buffers, creating and maintaining the pH gradient under strong electric fields. The review ends with a mention of the major contributions of B. J. Radola to this field, namely analytical and preparative IEF in granulated Sephadex layers and the development of ultrathin IEF, in polyacrylamide gels as thin as 20–100 μm. The latter technique paved the way to DNA sequencing gels and to CZE. The symptoms of decay are here presented through the simulations of Mosher and Thormann, clearly indicating an isotachophoretic mechanism for pH gradient decay with time. The decay of IEF was the birth of IPGs.
Curved DNA molecules migrate anomalously slowly in polyacrylamide gels even at zero gel concentration
Authors: Stellwagen Nancy C.
Published: January 2006

The electrophoretic mobilities of curved and normal DNA molecules of the same size have been measured in polyacrylamide gels containing various acrylamide concentrations and cross‐linker ratios. Ferguson plots were constructed to extrapolate the observed mobilities to zero gel concentration. The DNA samples were two 147‐bp restriction fragments, called 12A and 12B, obtained from the MspI digestion of plasmid pBR322, and head‐to‐tail multimers of each fragment. Fragment 12A is stably curved and migrates anomalously slowly in polyacrylamide gels; fragment 12B has the conformation of normal DNA and migrates with normal electrophoretic mobilities. The extrapolated mobilities of the curved fragment 12A and its multimers at zero gel concentration are lower than the extrapolated mobilities of the normal fragment 12B and its multimers. The free solution mobility of the curved fragment 12A, measured by CE, is also lower than that of the normal fragment 12B. The combined results indicate that the extrapolated mobilities observed for curved DNA molecules at zero polyacrylamide gel concentration reflect the intrinsic differences in their free solution mobilities.
Comparison of the use of anionic and cationic surfactants for the separation of steroids based on MEKC and sweeping‐MEKC modes
Authors: Shen Hui‐Ju , Lin Cheng‐Huang
Published: January 2006

In attempts to improve the selectivity and sensitivity of steroid separation and to determine their migration order, a comparison of the use of anionic and cationic surfactants based on the MEKC and sweeping‐MEKC modes was made. A mixture of six steroids (progesterone, 17‐hydroxy progesterone, 11‐deoxycortisol, corticosterone, cortisone, and cortisol) could be separated and detected by means of the CE/UV‐absorption method. The order of migration time for these steroids was compared under various conditions, including acidic/alkaline buffers, anionic/cationic surfactants, and positive/negative applied voltage, causing the direction of the EOF and the migration of micelles to change. The major rules for generally predicting the migration order of steroids are summarized. The detection limits were significantly improved when the sweeping‐MEKC mode was applied.
Determination of antidepressants in surface and waste water samples by capillary electrophoresis with electrospray ionization mass spectrometric detection after preconcentration using off‐line solid‐phase extraction
Authors: Himmelsbach Markus , Buchberger Wolfgang , Klampfl Christian W.
Published: January 2006

A method for the quantitative determination of seven major antidepressants in surface waters and sewage treatment plant effluents by CE using ESI‐MS is presented. Calibration curves for the selected analytes were prepared in Milli‐Q purified water and Danube river water extract covering a concentration range of at least one order of magnitude. LODs achieved were between 6 and 13 μg/L for Trazodone and 39 and 53 μg/L for Sertraline in the Milli‐Q purified water and Danube river water matrix, respectively. For sample preparation eight different SPE materials were investigated. Best results were obtained for a resin based on hydrophilic divinylbenzene (recoveries from Milli‐Q purified water 93–96%; from Danube river water 85–99%). Finally, a series of eight sewage treatment plant effluents were investigated with respect to their content in the selected antidepressants. Six of these samples were tested positive for antidepressants, in particular Venlafaxine, Citalopram and Trazodone in concentrations between 36 and 322 ng/L.
Fluorescence imaging of sample zone narrowing and dispersion in a glass microchip: The effects of organic solvent (acetonitrile)–salt mixtures in the sample matrix and surfactant micelles in the running buffer
Authors: Jia Zhijian , Lee Yi‐kuen , Fang Qun , Huie Carmen W.
Published: January 2006

A mismatch in the EOF velocities between the sample zone and running buffer region is known to generate pressure‐driven, parabolic flow profile of the sample plug in electrokinetic separation systems. In the present study, video fluorescence microscopy was employed to capture real‐time dynamics of the sample plug (containing fluorescein as the probe molecule) in a discontinuous conductivity system within a glass microchip, in which the sample matrix consisted of a mixture of ACN and salt (NaCl), and the running buffer contained sodium cholate (SC) micelles as the pseudo‐stationary phase (i.e., performing “ACN stacking” in the mode of MEKC). Upon application of the separation voltage, the video images revealed that zone narrowing and broadening of the probe molecules occurred as the sample plug headed toward the cathode during the initial time period, probably resulting in part from the stacking/sweeping, and destacking of the SC micelles at the boundaries between the sample zone and running buffer. Interestingly, a second sample zone narrowing event can be observed as the sample plug moved further toward the cathode, which could be attributed to the sweeping of the slower moving probe molecules by the faster moving SC micelles that originated from the anode. This phenomenon was studied as a function of pH, sample plug length, as well as the concentration of organic solvent and salt in the sample matrix. The data suggested that the presence of large amounts of an organic solvent (such as ACN or methanol) and salts in the sample matrix not only induces sample dispersion due to the formation of a pressure‐driven (hydrodynamic) flow, but may also lead to the formation of a double sample zone narrowing phenomenon by altering the local EOF dynamics within the separation system.
Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenates
Authors: Dickow Cardoso Carmem , Polisel Jabor Valquíria A. , Sueli Bonato Pierina
Published: January 2006

A rapid, selective, and low‐cost chiral capillary electrophoretic method was developed for the simultaneous analysis of hydroxychloroquine (HCQ) and its three chiral metabolites: desethylchloroquine (DCQ), desethylhydroxychloroquine (DHCQ), and bisdesethylchloroquine (BDCQ) in the microsomal fraction of liver homogenates. After liquid–liquid extraction using toluene as extracting solvent, the drug and metabolites were resolved on a fused‐silica capillary (50 μm ID, 50 cm total length, and 42 cm effective length), using 100 mmol/L of Tris/phosphate buffer, pH 9.0 containing 1% w/v sulfated‐β‐CD and 30 mg/mL hydroxypropyl‐β‐CD. Detection was carried out at 220 nm. The extraction procedure was efficient in removing endogenous interferents, and low values (≤15%) for CVs and deviation from theoretical values were demonstrated for both within‐day and between‐day assays. The quantitation limit was 125 ng/mL with linear response over the 125–2000 ng/mL of concentration range for all metabolites. After validation, the method was used for an in vitro metabolism study of HCQ. The major HCQ metabolite formed by microsomal enzymes was (−)‐(R)‐DHCQ.
The added value of a multidisciplinary approach in diagnosing dementia: a review
Authors: Wolfs Claire A. G. , Dirksen Carmen D. , Severens Johan L. , Verhey Frans R. J.
Published: January 2006

Background

The impact of dementia constitutes a major public health challenge to our society. A multidisciplinary approach to dementia is generally recommended.

Objective

The objective of this review is to give an overview of the reported empirical studies on the added value of a multidisciplinary approach to diagnosing dementia, i.e. whether differences can be found between diagnostic multidisciplinary approaches, and/or monodisciplinary ones with respect to the diagnostic outcomes, the impact of diagnostics and their effects on quality of life and costs.

Method

Critical review of studies which involve a multidisciplinary assessment of dementia. Literature was systematically searched in a number of international databases (Medline, PsychInfo, Pubmed and EconLit). A first selection was based on screening titles by one author. Interrater reliability was determined by scoring all abstracts by two authors. The reliability of selecting full articles was based on scoring a random sample by two authors. Kappa values were calculated. The Kappa statistic (k) was also used as an indicator of the diagnostic agreement between single disciplines and multidisciplinary teams.

Results

Five studies were identified as relevant for the purpose of this review. The most important outcome was the level of diagnostic agreement between single disciplines and multidisciplinary teams (MTs). Overall, there was substantial agreement (kappa: 0.37–0.76) on the diagnosis dementia (syndrome), but not on the subtypes (aetiology) (AD: 0.26–0.60; VD: 0.35–0.52; depression: 0.30–0.46). Diagnoses also differed between the disciplines.

Conclusions

Merely studies on diagnostic accuracy were found, all using different reference standards. Kappa values were chosen as outcome measure and every diagnosis was considered of equal value. Therefore, the added value could not definitively be demonstrated. However, the potential added value of a multidisciplinary approach to diagnosing dementia probably lies in the ability to differentiate among the subtypes of dementia and to detect comorbid psychiatric conditions such as depression. Disciplines within an MT complement each other in establishing a specific diagnosis, which is considered to be the added value of such a multidisciplinary team. Copyright © 2006 John Wiley & Sons, Ltd.
Liver endothelial cells promote LDL-R expression and the uptake of HCV-like particles in primary rat and human hepatocytes
Authors: Nahmias Yaakov , Casali Monica , Barbe Laurent , Berthiaume Francois , Yarmush Martin L.
Published: January 2006

Low-density lipoprotein (LDL) is an important carrier of plasma cholesterol and triglycerides whose concentration is regulated by the liver parenchymal cells. Abnormal LDL regulation is thought to cause atherosclerosis, while viral binding to LDL has been suggested to facilitate hepatitis C infection. Primary hepatocytes quickly lose the ability to clear LDL during

in vitro

culture. Here we show that the coculture of hepatocytes with liver sinusoidal endothelial cells (LSEC) significantly increases the ability of hepatocytes to uptake LDL

in vitro

. LDL uptake does not increase when hepatocytes are cocultured with other cell types such as fibroblasts or umbilical vein endothelial cells. We find that LSECs induce the hepatic expression of the LDL receptor and the epidermal growth factor receptor. In addition, while hepatocytes in single culture did not take up hepatitis C virus (HCV)-like particles, the hepatocytes cocultured with LSECs showed a high level of HCV-like particle uptake. We suggest that coculture with LSECs induces the emergence of a sinusoidal surface in primary hepatocytes conducive to the uptake of HCV-like particles.

In conclusion

, our findings describe a novel model of polarized hepatocytes

in vitro

that can be used for the study of LDL metabolism and hepatitis C infection.

Supplementary material for this article can be found on the HEPATOLOGY website (

http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html

).

(Hepatology 2006;43:257–265.)