bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative evaluation of the treatment efficacy of suberoylanilide hydroxamic acid (SAHA) and paclitaxel in ovarian cancer cell lines and primary ovarian cancer cells from patients
Authors: Sonnemann Jürgen , Gänge Jennifer , Pilz Sabine , Stötzer Christine , Ohlinger Ralf , Belau Antje , Lorenz Gerd , Beck James F 
Published: July 2006

Abstract

Background
In most patients with ovarian cancer, diagnosis occurs after the tumour has disseminated beyond the ovaries. In these cases, post-surgical taxane/platinum combination chemotherapy is the "gold standard". However, most of the patients experience disease relapse and eventually die due to the emergence of chemotherapy resistance. Histone deacetylase inhibitors are novel anticancer agents that hold promise to improve patient outcome.

Methods
We compared a prototypic histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), and paclitaxel for their treatment efficacy in ovarian cancer cell lines and in primary patient-derived ovarian cancer cells. The primary cancer cells were isolated from malignant ascites collected from five patients with stage III ovarian carcinomas. Cytotoxic activities were evaluated by Alamar Blue assay and by caspase-3 activation. The ability of SAHA to kill drug-resistant 2780AD cells was also assessed.

Results
By employing the cell lines OVCAR-3, SK-OV-3, and A2780, we established SAHA at concentrations of 1 to 20 μM to be as efficient in inducing cell death as paclitaxel at concentrations of 3 to 300 nM. Consequently, we treated the patient-derived cancer cells with these doses of the drugs. All five isolates were sensitive to SAHA, with cell killing ranging from 21% to 63% after a 72-h exposure to 20 μM SAHA, while four of them were resistant to paclitaxel (i.e., <10% cell death at 300 nM paclitaxel for 72 hours). Likewise, treatment with SAHA led to an increase in caspase-3 activity in all five isolates, whereas treatment with paclitaxel had no effect on caspase-3 activity in three of them. 2780AD cells were responsive to SAHA but resistant to paclitaxel.

Conclusion
These ex vivo findings raise the possibility that SAHA may prove effective in the treatment of paclitaxel-resistant ovarian cancer in vivo.
Streptococcal Receptor Polysaccharides: Recognition Molecules for Oral Biofilm Formation
Authors: Yoshida Yasuo , Palmer Robert J , Yang Jinghua , Kolenbrander Paul E , Cisar John O 
Published: July 2006

Abstract

Background
Strains of viridans group streptococci that initiate colonization of the human tooth surface typically coaggregate with each other and with Actinomyces naeslundii, another member of the developing biofilm community. These interactions generally involve adhesin-mediated recognition of streptococcal receptor polysaccharides (RPS). The objective of our studies is to understand the role of these polysaccharides in oral biofilm development.

Methods
Different structural types of RPS have been characterized by their reactions with specific antibodies and lectin-like adhesins. Streptococcal gene clusters for RPS biosynthesis were identified, sequenced, characterized and compared. RPS-producing bacteria were detected in biofilm samples using specific antibodies and gene probes.

Results
Six different types of RPS have been identified from representative viridans group streptococci that coaggregate with A. naeslundii. Each type is composed of a different hexa- or heptasaccharide repeating unit, the structures of which contain host-like motifs, either GalNAcβ1-3Gal or Galβ1-3GalNAc. These motifs account for RPS-mediated recognition, whereas other features of these polysaccharides are more closely associated with RPS antigenicity. The RPS-dependent interaction of S. oralis with A. naeslundii promotes growth of these bacteria and biofilm formation in flowing saliva. Type specific differences in RPS production have been noted among the resident streptococcal floras of different individuals, raising the possibility of RPS-based differences in the composition of oral biofilm communities.

Conclusion
The structural, functional and molecular properties of streptococcal RPS support a recognition role of these cell surface molecules in oral biofilm formation.
Child health inequities in developing countries: differences across urban and rural areas
Authors: Fotso Jean-Christophe 
Published: July 2006

Abstract

Objectives
To document and compare the magnitude of inequities in child malnutrition across urban and rural areas, and to investigate the extent to which within-urban disparities in child malnutrition are accounted for by the characteristics of communities, households and individuals.

Methods
The most recent data sets available from the Demographic and Health Surveys (DHS) of 15 countries in sub-Saharan Africa (SSA) are used. The selection criteria were set to ensure that the number of countries, their geographical spread across Western/Central and Eastern/Southern Africa, and their socioeconomic diversities, constitute a good yardstick for the region and allow us to draw some generalizations. A household wealth index is constructed in each country and area (urban, rural), and the odds ratio between its uppermost and lowermost category, derived from multilevel logistic models, is used as a measure of socioeconomic inequalities. Control variables include mother's and father's education, community socioeconomic status (SES) designed to represent the broad socio-economic ecology of the neighborhoods in which families live, and relevant mother- and child-level covariates.

Results
Across countries in SSA, though socioeconomic inequalities in stunting do exist in both urban and rural areas, they are significantly larger in urban areas. Intra-urban differences in child malnutrition are larger than overall urban-rural differentials in child malnutrition, and there seem to be no visible relationships between within-urban inequities in child health on the one hand, and urban population growth, urban malnutrition, or overall rural-urban differentials in malnutrition, on the other. Finally, maternal and father's education, community SES and other measurable covariates at the mother and child levels only explain a slight part of the within-urban differences in child malnutrition.

Conclusion
The urban advantage in health masks enormous disparities between the poor and the non-poor in urban areas of SSA. Specific policies geared at preferentially improving the health and nutrition of the urban poor should be implemented, so that while targeting the best attainable average level of health, reducing gaps between population groups is also on target. To successfully monitor the gaps between urban poor and non-poor, existing data collection programs such as the DHS and other nationally representative surveys should be re-designed to capture the changing patterns of the spatial distribution of population.
Intra-thoracic desmoid tumour in a patient with a previous aortocoronary bypass
Authors: Borzellino Giuseppe , Minicozzi Anna Maria , Giovinazzo Francesco , Faggian Giuseppe , Iuzzolino Paolo , Cordiano Claudio 
Published: July 2006

Abstract

Background
Intra-thoracic desmoid tumours with mediastinal invasion are very rare. Although rare they have to be taken into account in the differential diagnosis of a thoracic mass and therapeutic options have to be weighted since surgical treatment may require wide excision.

Case presentation
A 48-year-old male diabetic, dyslipidaemic, former heavy smoker with psychiatric illness was operated by sternotomy for a triple aorto-coronary bypass 4 years before, presented with complains of recent onset such as constant and oppressive chest pain. At surgery a mass extending from the aortic arch into the entire anterior mediastinum and to most of the right pleural cavity was found. The mass was separated from sternal periosteum and vessels of aorto-coronary by pass were isolated starting from the aortic arch up to the pericardium. The histological examination revealed aggressive fibromatosis.

Conclusion
Although technically demanding, radical surgical excision is actually the most indicated therapeutic approach for intra-thoracic desmoid tumours.
Preparation, Characterization, and Some Properties of a T-Cage-Type S-Bridged RhIII4ZnII3 Heptanuclear Complex with a Defective [Zn3HO]5+ Core. Crystal Structure of Spontaneously Resolved [{Rh(aet)3}4Zn3HO]Br5 (aet = 2-Aminoethanethiolate)
Authors: Konno Takumi , Okamoto Ken-ichi , Hidaka Jinsai 
Published: July 2006

Abstract
The reaction of fac(S)-[Rh(aet)3] with ZnBr2 in water produced a T-cage-type S-bridged polynuclear complex with a “defective” [Zn3HO]5+ core, [{Rh(aet)3}4Zn3HO]Br5 (1Br5), which was subject to spontaneous resolution to give and isomers. 1 was also optically resolved into the two isomers with use of [Sb2(R,R-tartrate)2]2−. The crystal structure and absolute configuration for the spontaneously resolved isomer were determined by X-ray crystallography. [{Rh(C2H6NS)3}4Zn3HO]Br5·9H2O, crystallizes in the cubic space group P213 with a = 19.186 (1) Å, V = 7062.1 (4) Å3, Z = 4, and R = 0.0648. In 1 the four octahedral fac(S)-[Rh(aet)3] subunits are bound to a quasi-tetrahedral [Zn3HO]5+ core in a tetrahedral arrangement. The chiral configurations are regulated to Δ for all fac(S)-[Rh(aet)3] subunits and R for all asymmetric bridging sulfur atoms in -1, giving a quasi-T symmetrical structure. 1 is unstable in water and convertible to a T-cage-type octanuclear complex with a “complete” [Zn4O]6+ core, [{Rh(aet)3}4Zn4O]6+ (2), and to a linear-type S-bridged trinuclear complex, [Co{Rh(aet)3}2]3+, by adding ZnBr2 and [CoCl(NH3)5]Cl2, respectively. The electronic absorption and circular dichroism (CD) spectral behavior of 1 are discussed in comparison with those of 2.
Structures and Properties of Ternary Copper(II) Complexes Involving a Halogen Substituted Phenylalanine and 2,2′-Bipyridine. Intermolecular Interactions between Halo and Organic Groups
Authors: Sugimori Tamotsu , Masuda Hideki , Yamauchi Osamu 
Published: July 2006

Abstract
Structural and spectroscopic studies have been performed on the ternary Cu(II) complexes containing 4-halophenylalanines (XPhe) (X = I or Br) and 2,2′-bipyridine (bpy). The absorption spectra of the 1 : 1 : 1 Cu(bpy)(XPhe) systems exhibited a single d–d peak at 605—608 nm (pH 6—7), and the band centered at ca. 320 nm due to the charge transfer interaction between the substituted phenyl ring and bpy was observed in the difference spectra in the near ultraviolet region. Three complexes with XPhe, [Cu(bpy)(Dl-IPhe)(NO3)] (1), [Cu(bpy)(Dl-BrPhe)(NO3)] (2), and [Cu(bpy)(l-IPhe)]ClO4 (3) were isolated as crystals, and the structures were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic space group, P21/n, with four molecules in a unit cell of dimensions a = 5.292(1), b = 27.315(8), c = 13.848(2) Å, β = 90.05(2)°. Complex 2 also crystallizes in the monoclinic space group, P21/n, with four molecules in a unit cell of dimensions a = 5.293(5), b = 27.18(1), c = 13.540(6) Å, β = 90.03(6)°. The Cu(II) ion in each complex is in a five-coordinate distorted square-pyramidal geometry. Complex 3 crystallizes in triclinic space group P1 with two independent molecules in the asymmetric unit in a unit cell of dimensions a = 18.329(4), b = 10.701(1), c = 5.9287(9) Å, α = 73.91(1), β = 90.02(2), γ = 105.93(2)°. The Cu(II) ion is in a four-coordinate, slightly distorted square-planar geometry. The phenyl ring of XPhe in 1 and 2 is located perpendicular to the bpy plane, and no intramolecular stacking was observed. The phenyl ring of L-IPhe in 3 is tilted over the coordination plane to be stacked with bpy with the average spacing of 3.23 and 3.24 Å. The crystal structures revealed close contacts between the halogen atoms and the carbon atoms of the bpy ring in complexes 1 and 2, with the distances of I···C = 3.54 Å and Br···C = 3.47 Å for 1 and 2, respectively. A close contact between the iodine and carbonyl oxygen was also detected in the crystal structure of 3 with the I···O distance of 3.1 Å. Possible significance of these interactions has been discussed in relation to thyroid hormone-receptor bonding.
Direct Electrochemistry of Nitrite Reductase from Achromobacter cycloclastes IAM 1013
Authors: Kohzuma Takamitsu , Shidara Sohsuke , Suzuki Shinnichiro 
Published: July 2006

Abstract
The cyclic voltammetry of the nitrite reductase from Achromobacter cycloclastes IAM 1013 exhibited well defined voltammetric response at a di-4-pyridyl disulfide (4-pyds) modified gold electrode in the presence of A. cycloclastes apopseudoazurin. The midpoint potential, E1/2, of the native and type II copper-depleted (T2D) nitrite reductase obtained from the voltammogram were estimated to be 240 mV and 204 mV vs. NHE, respectively. The almost identical current value of the native and T2D reductase suggested that the voltammetric behavior contributed from the type 1 copper site. When nitrite was added into the nitrite reductase solution (pH 7.0), an enhanced sigmoidal cathodic current-potential curve indicating the catalytic regeneration of oxidized nitrite reductase was observed. The rate constant of nitrite reduction and the Michaelis constant, Km, of the native reductase were estimated to be 5 × 102 mol−1 dm3 s−1 and 7 × 10−4 mol dm−3, respectively. The rate constant of the nitrite reduction and the Km value of T2D nitrite reductase were also estimated to be 1 × 102 mol−1 dm3 s−1 and 3 × 10−3 mol dm−3, respectively. These results suggested that the nitrite reduction activity is closely related with type II copper site.
Spin Trapping as Applied to Radicals Produced by Chemical Reaction. III. Intermediates of the Reactions of Dibenzoyl Peroxide with Diethylamine and Diphenylamine
Authors: Nishimura Norio , Nakamura Tatsuya , Sueishi Yoshimi , Yamamoto Shunzo 
Published: July 2006

Abstract
The reactions of dibenzoyl peroxide (BPO) with diethylamine (DEA) and diphenylamine (DPA) have been studied by means of an ESR technique combined with spin-trapping. In the case of the DEA/BPO system, diethylnitroxide was formed, while for the DPA/BPO system diphenylaminyl was detected. Three kinds of traps (N-t-benzylidene-t-butylamine N-oxide, 2-methyl-2-nitrosopropane, and 2,4,6-tri-t-butylnitrosobenzene) were used. Different kinds of spin-adducts were formed depending on such conditions as the steric circumstances, radical stabilities and solvent effects. The differences in the reaction mechanisms for these systems are discussed.
Electrophilic Substitution of Monosubstituted Pyrenes
Authors: Minabe Masahiro , Takeshige Shouji , Soeda Yuuji , Kimura Takao , Tsubota Motohiro 
Published: July 2006

Abstract
Bromination and the Friedel–Crafts acetylation of monosubstituted pyrenes were examined. Acetylation of 1-acetyl- and 1-ethylpyrene occurred at the 8-, 6-, or 3-position, but the reaction of 1-methoxypyrene afforded only the 8- and 6-acetyl derivatives. By acetylation, 4-acetylpyrene yielded the 1- and 6-acetyl compounds, and 4-ethylpyrene gave the 6- and 8- derivatives. Also, 4-bromopyrene afforded the corresponding 8-, 6-, and 1-acetyl derivatives by the same reaction. Bromination of 1-ethyl- and 4-ethylpyrene yielded the 8- and 6-bromides, but the reaction of 1-nitro- and 1-bromopyrene took place at the 6-, 8-, or 3-position. The formation ratio of these regioisomers differs by the substituents. The regioselectivity on the acetylation accords in some degree with the prediction based on the 13C NMR chemical shift of each position. The relative rates of these electrophilic substitutions correlate to the substituent constant, σ+, of the substituent attached to the pyrene.
Crystal Structure and Conformational Analysis of 3β,17β-Diacetoxy-8,9-seco-5α-androstane-8,9,11-trione
Authors: Okada Kenji , Koyama Hirozo 
Published: July 2006

Abstract
The crystal and molecular structures of the title compound 1 have been determined by direct methods. The crystals are monoclinic, space group P21, with a = 12.512(2), b = 7.436(2), c = 12.252(2) Å, β = 102.62(1)°, Z = 2. The structure was refined by full-matrix least-squares calculations to a final R of 0.056 for 2268 independently observed reflections. This tricylic compound consists of five-, six-, and ten-membered rings and is slightly bent, including two OAc side chains. The six-membered ring A has a typical chair conformation and the ten-membered ring B adopts a chair-chair conformation. Ring C is a normal β envelope. The ring junctions of both A/B and B/C are trans fusion. Two double bonds [C(8)=O(2), C(11)=O(4)] and two methyl groups [C(18), C(19)] of ring B are oriented α face, and one double bond [C(9)=O(3)] is on the β face of this ring. The O–C–O bond distances in the OAc side chains show partial double-bond characters.
An Effective Method for Acylation of Weakly Nucleophilic Anilines with Silyl Carboxylates via Mixed Anhydrides
Authors: Miyashita Mitsutomo , Shiina Isamu , Mukaiyama Teruaki 
Published: July 2006

Abstract
In the presence of a catalytic amount of active titanium(IV) salt generated in situ from 1 mol of TiCl4 and 2 mol of AgOTf, weakly nucleophilic anilines react under mild conditions with nearly equimolar amounts of silyl carboxylates to afford the corresponding anilides in excellent yields using 4-(trifluoromethyl)benzoic anhydride. The mixed anhydride formed in situ from trimethylsily acetate and 4-(trifluoxomethyl)benzoic anhydride, a key intermediate of this reaction, was detected by 1H NMR experiment. Further, it was shown that the reaction of the mixed anhydrides and 2-nitroaniline was faster than that of the corresponding homo anhydrides and 2-nitroaniline.
Selective Oxidation of the α-Methylene of the Bridge in Ferrocenophanes with Silver Oxide or Silver Perchlorate/Sodium Methoxide
Authors: Hisatome Masao , Watanabe Jun , Yamakawa Koji 
Published: July 2006

Abstract
The treatment of ferrocenophanes with AgO, Ag2O or AgClO4/CH3ONa in methanol gave oxidized products at the α-methylene of the bridge. In the reaction of [m][n]ferrocenophanes (m, n = 3, 4, 5; m &gt; n), the α-methylene of the longest bridge [m] was oxidized in preference to that of the shorter bridge [n]. A reaction mechanism via a radical and/or cation species on the α-methylene of the bridge is proposed.
Synthetic Photochemistry. LXII. The Photoaddition of 4-Methyl-2-oxo-γ-valerolactone to Cycloalkenes
Authors: Hatsui Toshihide , Kitashima Toshio , Takeshita Hitoshi 
Published: July 2006

Abstract
Photocycloaddition of 4-methyl-2-oxo-γ-valerolactone to cycloalkenes gave [2+2] cycloadducts, together with the ene reaction products. The stereostructures of photoproducts were identified by detailed NMR spectral analyses including NOE experiments. The photocycloadducts were convertible to (2-alkenylcycloalkyl)glyoxalic acids.
Mechanistic Studies on trans-Dicarbonyl Phosphine Complexes of Molybdenum(I)
Authors: Abdel-Hamid Refat , El-Samahy Ahmed A , Rabia Mostafa K M , Taylor Norman , Shaw Bernard L 
Published: July 2006

Abstract
The electrode mechanism of trans-dicarbonyl phosphine complexes of molybdenum(I), trans-[Mo(CO)2(P-P)2]PF6 [where P-P = ph2PCH2CH2Pph2(dppe), or ph2PCH=CHPph2 (dppen)] was investigated by cyclic voltammetry and convolution and deconvolution potential sweep voltammetry in 0.1 mol dm−3 TBAP/CH2Cl2 solution at a platinum electrode. The complexes are both oxidized and reduced in one-electron processes. The oxidation and reduction processes are follows a well-defined ECirrev mechanism. Digital simulation and comparison with the experimental cyclic voltammetric results was used for determination of homogeneous and heterogeneous rate constants values.
An X-Ray RDF Study on the Glass 50AgI–25Ag2O–25MoO3
Authors: Patnaik S , Seshasayee M , Aravamudan G , Ohtaki Hitoshi 
Published: July 2006

Abstract
A structural investigation using an X-ray RDF (radial distribution function) technique was carried out for a glass of composition 50AgI–25Ag2O–25MoO3 (in mole% units). Results indicated the presence of strong Ag–I interactions at rAg–I = 287 pm and the average number of iodine atoms around an Ag atom, nAg–I was 0.77. Two Ag–O interactions characterized by rAg–O = 197 pm, nAg–O = 1.8 and rAg–O = 234 pm, nAg–O = 2.6 were also observed. The structural parameters of the glass former MoO3 were given as rMo–O = 198 pm and nMo–O = 5.5. The results showed that AgI was dispersed in the glassy matrix.
Kinetic and Equilibrium Investigation of the Proton Uptake Process in the Complex Formation between Counter-Charged Ionic Polypeptides
Authors: Sano Takayuki , Nakatsuka Thoru , Inoue Katsuaki 
Published: July 2006

Abstract
To clarify the mechanism of polymer complex formation between counter-charged polymers, kinetic and equilibrium experiments concerning the complexation of poly(l-α-glutamic acid) (PGA) with poly (l-α-lysine) (PLL) were performed at around pH 5.5 by the stopped-flow method. The reaction kinetics observed with electric conductivity detection and direct proton detection using the hydrogen ion-sensitive field-effect transistor suggests that the complex formation between these polymers proceeds through two processes of a fast proton release within 10 ms and a slow proton uptake within a few seconds. Further experiments using the various chain lengths of PGA and a variety of combinations of polymers and their counter-charged small ion, (e.g., PGA and amines or metal ions, PLL and carboxylic acids) have revealed that slow proton uptake in their complex formation is specific for a system which includes both a polymer and its counter-charged ions of divalent or more, and that this proton uptake is due to rearrangement of the polymer after fast electrostatic binding as a cooperative process.
Vertical Ionization Potentials of Alkoxides in Solution
Authors: Sakai Kanna , Watanabe Iwao , Yokoyama Yu 
Published: July 2006

Abstract
The photoelectron-emission threshold energies were determined for aqueous and alcoholic solutions of potassium hydroxide and potassium metal. The energies correspond to the vertical ionization potentials of the solutes. The results are in accord with the fact that in alcohol-rich solutions the hydroxide ion reacts with alcohol to produce the alkoxide ion. The threshold energy for the alkoxide ion reflects the ionization potential of the alkoxide ion in a vacuum and the solvation effect. The difference in the ionization potential in a vacuum and in a solution, which is due to the solvation effect, was found to correlate with the acceptor number of the solvent.
Transmembrane Rectified Electron Transfer through π-Conjugated Electroactive Langmuir–Blodgett Monolayers on Gold Electrodes
Authors: Kunitake Masashi , Nasu Kenji , Manabe Osamu , Nakashima Naotoshi 
Published: July 2006

Abstract
Novel amphiphiles with π-conjugated electroactive groups, 1-methyl-4-[2-[4-[2-(4-pyridyl)vinyl]phenyl]vinyl]pyridinium perchlorate (1), and 1-methyl-4-[2-[4-[2-(4-quinolyl)vinyl]phenyl]vinyl]quinolinium perchlorate (2), were designed and synthesized. Both compounds formed expanded monolayers at air–water interfaces. The monolayers transferred on gold disk electrodes at 25 mN m−1 by the Langmuir–Blodgett technique (horizontal lifting method) show one electron reduction/oxidation couple: Epa = −0.86 V, Epc = −1.08 V vs. SCE for 1/Au and Epa = −0.78 V, and Epc = −0.84 V vs. SCE for 2/Au. Rectified transmembrane electron transfer through the LB monolayers of 1 and 2 on gold electrodes to [Fe(CN)6]3− in aqueous solutions has been proved by cyclic voltammetry and potential-step chronocoulometry.