bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and analytical characterization of novel pyridyl‐substituted 1,1′‐ethenedithiolato complexes
Authors: Schubert Karsten , Goerls Helmar , Weigand Wolfgang
Published: July 2005

Some 1,1′‐ethenedithiolato complexes of nickel(II), palladium(II), and platinum(II) with different phosphine ligands, such as PPh3, PEt3, and dppe were prepared. Starting from 2‐, 3‐ as well as 4‐pyridyl methyl ketone, the complexes 1–15 were obtained in an one‐pot synthesis through reaction with carbon disulfide, using potassium‐tert‐butylate as a base. They were characterized by 1H, 13C, and 31P NMR, mass spectra, infrared spectra, and UV–VIS spectra. The molecular structures of the (Ph3P)2PdII complex 9 containing the 3‐pyridyl‐ethenedithiolato ligand and of the (Et3P)2PtII complex 12 containing the 4‐pyridyl‐ethenedithiolato ligand were determined. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:369–378, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20103
Preparation of 1,3‐diphosphabuta‐1,3‐dienes from sterically encumbered phosphaalkyne and phosphaethenyllithium
Authors: Ito Shigekazu , Miyake Hideaki , Sugiyama Hiroki , Yoshifuji Masaaki
Published: July 2005

Kinetically stabilized 2‐lithio‐1‐(2,4,6‐tri‐t‐butylphenyl)‐1‐phosphapropene was allowed to react with a bulky phosphaalkyne Mes*CP (Mes* = 2,4,6‐t‐Bu3C6H2) followed by quenching with iodomethane or benzyl bromide to give the corresponding 1,3‐diphosphabuta‐1,3‐dienes. The presence of the bulky Mes* group on the 1‐phosphorus atom prevents intramolecular [2+2] cyclization and gave the PCPC skeleton, whereas Mes*CP reacted with half an equivalent of nucleophile to afford the PCPC four‐membered ring compounds. X‐ray crystallography of 4‐benzyl‐1,3‐diphosphabuta‐1,3‐diene confirmed the molecular structure showing conjugation on the 1,3‐diphosphabuta‐1,3‐diene moiety. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:357–360, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20104
Crystal structure of germanium(II) dichloride solvated by tetrahydrofuran
Authors: Tian Xin , Pape Tania , Mitzel Norbert W.
Published: July 2005

The thermally highly unstable tetrahydrofuran solvate of germanium(II) dichloride (GeCl2 · 2THF) was crystallized, and its crystal structure was determined. It consists of a chain of GeCl2 units connected by secondary Cl···Ge contacts [3.846(2) Å] in which each Ge atom is coordinated to two molecules of THF. Two weak hydrogen bonds of the CH ··· ClGe type in GeCl2 · 2THF were also detected both with lengths of 2.90(3) Å. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:361–363, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20105
PH‐functional o‐phosphinophenols— synthesis via methoxymethylethers and screening tests for Ni‐catalyzed ethylene polymerization
Authors: Heinicke Joachim , He Mengzhen , Karasik Andrej A. , Georgiev Igor O. , Sinyashin Oleg G. , Jones Peter G.
Published: July 2005

Various primary and secondary 2‐phosphinoaryl methoxymethylethers were prepared via orthometallation of methyl‐ and methoxy‐substituted aryl methoxymethylethers and subsequent reaction with aminochlorophosphines, followed by alcoholysis and reduction with excess LiAlH4. Incomplete reduction provides 2‐methoxymethoxy‐substituted cyclotetraphosphines, isolated and characterized by X‐ray crystal structure analysis in one case. An example of the facile P‐alkylation of primary to secondary representatives is also given. Secondary 2‐phosphinophenols, obtained by selective cleavage of the MOM‐protection group, and even the primary 2‐phosphino‐4‐methylphenol react with Ni(COD)2 to form ethylene polymerization catalysts. 4‐Methoxy groups cause a strong increase of the molecular weights and a bimodal molecular weight distribution of the polymerization products; neither effect is observed for tertiary phosphinophenolate/Ni polymerization catalysts. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:379–390, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20107
Synthesis and magnetic properties of new dinuclear iron(II) complexes of a phenylene‐bridge shiff base analogue dinucleating ligand
Authors: Weber Birgit , Kaps Eike
Published: July 2005

The synthesis and magnetic behavior of four new dinuclear iron(II) complexes Fe22a‐d × 4Py with the iron in an octahedral coordination sphere is presented in this paper. The complex c is a high‐spin complex over the whole temperature range investigated, while the complexes a,b, and d perform a partial low‐spin ⇔︁ high‐spin spin transition. In case of Fe22b × 4Py, X‐ray structure analysis of the HS/LS state was possible, showing that in one molecule both iron centers are either in the low‐spin or sin the high‐spin state. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:391–397, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20108
Reactive EC(p‐p)π‐systems 53 [1]: Reactivity studies on perfluoro‐2‐arsapropene: [2+2]‐cycloaddition reactions and quantum chemical calculations
Authors: Albers Thomas , Grobe Joseph , Van Duc Le , Maulitz Andreas H. , Würthwein Ernst‐Ulrich
Published: July 2005

The extremely labile perfluoro‐2‐arsapropene F3CAsCF2 (1) has been generated by an improved pyrolysis process of Me3SnAs(CF3)2 and found to be stabilized by the presence of hexamethyldisiloxane and tert‐butylphosphaethyne, thus allowing (i) reactivity studies with alkyne derivatives like tBuCP, (iPr)2NCP, MeCCN(iPr)2, HCCOEt and (ii) a full NMR investigation of 1 (19F, 13C). Due to the instability of 1 and some of the products, the [2+2]‐cycloaddition reactions gave the expected arsaphospha‐ and arsa‐cyclobutene derivatives, respectively, in moderate to good yields, but in some cases contaminated with side and/or decomposition products. Unequivocal characterization of the novel compounds was accomplished by spectroscopic in‐ vestigations (1H, 13C, 19F, 31P NMR, IR, MS) supported by comparison with the data of the more stable phosphorus analogues. An interesting isomerization was observed for the 2‐dialkylamino‐4,4‐difluoro‐ 1‐trifluoromethyl‐1‐arsa‐3‐phospha‐2‐cyclobutenes yielding the more stable 3‐dialkylamino‐2,4‐difluoro‐ 1‐trifluoromethyl‐1‐arsa‐2‐phospha‐3‐cyclobutenes. Quantum chemical calculations [B3LYP/6‐311+ G(d,p)] of HAsCH2, F3CAsCF2, and F3CPCF2 were carried out to compare the length of the AsC double bond with the literature data and to elucidate substituent effects on its electronic structure. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:406–419, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20118
The thermodynamic stability of P8, A CBS‐Q study
Authors: Denk Michael K. , Hezarkhani Azardokht
Published: July 2005

The thermodynamic stabilities of P2, P4, and three P8 cage structure were investigated through high‐precision CBS‐Q calculations. The CBS‐Q values for the bond energy of P2 (ΔEo: +115.7 kcal mol−1) and the formation of P4 from P2 (Δ Eo:‐56.6 kcal mol−1) were in excellent agreement with the experimental values (Eo: +117 and ‐56.4 kcal mol−1 respectively). Among the P8 cages, the cubane structure was the least stable (Δ Eo +37 kcal vs. 2×P4). The most stable P8 isomer adopts a cuneane structure resembling S4N4, and is more stable than white phosphorus at T = 0 K (Δ Eo −3.3 kcal mol−1), but still unstable under standard conditions for entropic reasons (Δ Go of +8.1 kcal mol−1 vs. 2×P4). The CBS‐Q energies represent significant revisions (6–20 kcal mol−1) of previous computational predictions obtained by high‐level single method calculations. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:453–457, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20119
Protonation of some cyclic triphosphenium ions
Authors: Burton Jenny D. , Deng Robert M. K. , Dillon Keith B. , Monks Philippa K. , J. Olivey Richard
Published: July 2005

Several cyclic triphosphenium ions of various ring sizes have been successfully protonated to form the corresponding triphosphane di‐ium dications, either by a tBuCl/AlCl3 mixture and/or by triflic acid. The latter reagent appears to be harsher, however, sometimes leading to decomposition. The new dications have been identified in solution by 31P NMR spectroscopy; recording the spectra proton coupled as well as decoupled has enabled 1JPH as well as 1JPP to be evaluated in most cases. The protonated derivatives of three compounds could not be observed, with only decomposition products being detected. In the case of the triphosphenium ion derived from bis‐1,4‐diphenylphosphinobutane (dppb), clear spectroscopic evidence for an intermediate in the decomposition process of the di‐ium dication has been obtained, enabling a plausible mechanism to be proposed. In addition, a novel triphosphorus‐containing trication with a norbornane‐like structure has been detected, and characterized by single crystal X‐ray diffraction, as a minor product from the protonation of the triphosphenium ion derived from cis‐bis‐1,2‐diphenylphosphinoethene (dppE). © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:447–452, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20124
Coordination of phosphanide and trialkylsilylphosphanide ligands at pentacarbonyltungsten fragments: An NMR spectroscopic and structural investigation
Authors: Rotter Thomas , Karaghiosoff Konstantin , Mayer Peter , Westerhausen Matthias
Published: July 2005

Trialkylsilylphosphanide ligands as pentacarbonyltungsten adducts such as the anions [((CO)5W)2P(H)SiR3]− and [(CO)5W‐PHSiR3]− with R = Me, iPr, and tBu are prepared by the reaction of (thf)W(CO)5 with MP(H)SiR3 or by the metathesis reaction of ((OC)5W)2PHLi2 with ClSiR3 and characterized by NMR spectroscopy with a focus on 183W‐NMR experiments. The solvent‐separated ion pair (tmeda)K+ [((OC)5W)2P(H)SiiPr3]− crystallizes as a coordination polymer with a rather large PSi bond length of 228.1 pm. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:420–425, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20128
Enantiopure phosphacymantrene‐2‐carboxaldehyde and some of its derivatives
Authors: Deschamps Bernard , Mathey François
Published: July 2005

The resolution of η5(2‐formyl‐3,4‐dimethylphospholyl)(triphenylphosphine)‐manganesedicarbonyl 1 has been carried out by chromatography of the acetals derived from (S,S)‐1,2‐diphenylethane‐1,2‐diol. The enantiopure 2‐diphenylphosphinomethyl 4 and diphenylmethylimino 5 derivatives have been prepared from 1. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:458–460, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20130
[(α‐Imino)enamino]phosphonium salts from propyne iminium salts and a phosphorane imine
Authors: Rahm Rainer , Espenlaub Sigrid , Werz Udo R. , Maas Gerhard
Published: July 2005

Propyne iminium triflates R1C(N+R3R4)CCR2 CF3SO readily react with Ph3PNPh to form 1:1 adducts which formally result from a metathetical addition of the phosphorane imine across the triple bond of the alkyne. These adducts are best described as enamino‐phosphonium salts or iminio‐substituted phosphorus ylides. The configuration of these salts has been determined from NMR data and an X‐ray crystal structure analysis of salt 3h. The base‐induced elimination of the PPh3 substituent from enamino‐phosphonium salt 3a was studied. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:437–446, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20131
Effect of hydroxyapatite coating crystallinity on dissolution and osseointegration in vivo
Authors: Xue Weichang , Liu Xuanyong , Zheng Xuebin , Ding Chuanxian
Published: July 2005

Hydroxyapatite (HA) coating with different crystallinities were deposited by plasma spraying and vapor‐flame treatment process. Their crystallinities are about 55 and 98%, respectively. These coatings were implanted in cortical bone, muscle, and marrow of dogs. The dissolution and osseointegration behavior were evaluated by scanning electron microscope (SEM) observation histological analysis. The results obtained indicated that after implanted in muscle, a bone‐like apatite layer was formed on the surface of as‐sprayed coating, which was not observed on the surface of the treated coating. The as‐sprayed coating has the ability to induce new bone formation on its surface after implanted in marrow. In contrast, the treated coating displays a limited bone bioactivity. The vapor‐flame process diminishes the short‐term osseointegration properties of the HA coating, but no significant affection was found after three months implantation. Either in muscle or in cortical bone, treated coating exhibits higher stability than the as‐sprayed coating, in some conditions. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
The bone formation in vitro and mandibular defect repair using PLGA porous scaffolds
Authors: Ren Tianbin , Ren Jie , Jia Xiaozhen , Pan Kefeng
Published: July 2005

Highly porous scaffolds of poly(lactide‐co‐glycolide) (PLGA) were prepared by solution‐casting/salt‐leaching method. The in vitro degradation behavior of PLGA scaffold was investigated by measuring the change of normalized weight, water absorption, pH, and molecular weight during degradation period. Mesenchymal stem cells (MSCs) were seeded and cultured in three‐dimensional PLGA scaffolds to fabricate in vitro tissue engineering bone, which was investigated by cell morphology, cell number and deposition of mineralized matrix. The proliferation of seeded MSCs and their differentiated function were demonstrated by experimental results. To compare the reconstructive functions of different groups, mandibular defect repair of rabbit was made with PLGA/MSCs tissue engineering bone, control PLGA scaffold, and blank group without scaffold. Histopathologic methods were used to estimate the reconstructive functions. The result suggests that it is feasible to regenerate bone tissue in vitro using PLGA foams with pore size ranging from 100–250 μm as scaffolding for the transplantation of MSCs, and the PLGA/MSCs tissue engineering bone can greatly promote cell growth and have better healing functions for mandibular defect repair. The defect can be completely recuperated after 3 months with PLGA/MSCs tissue engineering bone, and the contrastive experiments show that the defects could not be repaired with blank PLGA scaffold. PLGA/MSCs tissue engineering bone has great potential as appropriate replacement for successful repair of bone defect. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Surface characterizations and corrosion resistance of nickel–titanium orthodontic archwires in artificial saliva of various degrees of acidity
Authors: Huang Her‐Hsiung
Published: July 2005

This study investigated the surface characterizations and corrosion resistance of as‐received commercial nickel–titanium (NiTi) dental orthodontic archwires from different manufacturers using a cyclic potentiodynamic test in artificial saliva with various acidities. An atomic force microscope was used to evaluate the surface topography of the NiTi wires. The surface chemical analysis of the passive film on the NiTi wires was characterized using X‐ray photoelectron spectroscopy and Auger electron spectroscopy. A scanning electron microscope, together with an energy‐dispersive spectrometer, was used to analyze the surface characterizations of the NiTi wires before and after the corrosion tests. Two‐way analysis of variance was used to analyze the corrosion‐resistance parameters with the factors of wire manufacturer and solution pH. The results showed that the surface structure of the passive film on the tested NiTi wires were identical, containing mainly TiO2, with small amounts of NiO. A different surface topography was observed on the NiTi wires from various manufacturers. The corrosion tests showed that both the wire manufacturer and solution pH had a statistically significant influence on the corrosion potential, corrosion rate, passive current, breakdown potential, and crevice‐corrosion susceptibility. The difference in the corrosion resistance among these NiTi dental orthodontic archwires did not correspond with the surface roughness and pre‐existing defects. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Indomethacin‐loaded methoxy poly(ethylene glycol)/poly(D,L‐lactide) amphiphilic diblock copolymeric nanospheres: Pharmacokinetic and toxicity studies in rodents
Authors: Kim So Yeon , Lee Young Moo , Kang Ju Seop
Published: July 2005

Biodegradable methoxy poly(ethylene glycol)/poly(D,L‐lactide) amphiphilic block copolymeric nanospheres were prepared for application as a particulate drug carrier. Drug‐loaded nanospheres (ML50) showed a narrow size distribution with the average diameter of <200 nm. When the feed weight ratio of indomethacin (IMC) to polymer was 1:1, the ML50 nanosphere having a relatively high drug‐loading efficiency of about 33.0% could be obtained. To investigate pharmacokinetic characteristics of IMC in rats, the IMC concentration in plasma was analyzed using a high‐performance liquid chromatography system after intravenous bolus injection of free IMC and IMC‐loaded ML50 nanospheres. ML50 nanosphere system exhibited a significant potential for sustained release of drug and showed slow clearance of IMC, but there was no significant effect on metabolism of IMC in the rats. Median lethal dose (LD50) and major organs (e.g., heart, lung, liver, and kidney) toxicities were determined using ICR mice to estimate the acute toxicity of ML50 nanospheres. The LD50 of ML50 nanospheres determined by Litchfield‐Wilcoxon method was about 1.54 g/kg. After the mice were intraperitoneally administered with a half dose of LD50 for 7 days, no significant histopathologic changes were observed in ML50‐treated mice compared with normal mice in the light and electron microscopic observations of major organs. This indicates that ML50 nanospheres might be a useful candidate as a novel sustained drug carrier for hydrophobic drugs. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Enhanced fixation of implants by bone ingrowth to titanium fiber mesh: Effect of incorporation of hydroxyapatite powder
Authors: Tsukeoka Tadashi , Suzuki Masahiko , Ohtsuki Chikara , Tsuneizumi Yoshikazu , Miyagi Jin , Sugino Atsushi , Inoue Takayuki , Michihiro Ryouichi , Moriya Hideshige
Published: July 2005

Tight fixation between bone and implant materials is of great importance for a successful outcome of procedures such as total knee arthroplasty (TKA) and total hip arthroplasty (THA). Titanium fiber mesh is an attractive structure for the establishment of tight fixation between bone and implant by bone ingrowth into the spaces among the fibers. Enhancement of bone ingrowth is desired not only for tight fixation but also for a fast recovery. Our hypothesis is that just the presence of hydroxyapatite (HA) particles ensures improved bone ingrowth, and that long‐term stability can be obtained by mechanical anchoring of bone in the spaces among titanium fibers. In this study, we examine our hypothesis by in vivo experiment using dog femur. HA particles were incorporated in titanium fiber mesh coated on titanium alloy rod by dipping in a slurry of HA with hydroxy‐propyl‐cellulose in an ethanol solution. Specimens were implanted for 3, 5, and 8 weeks, and were then compared with the results from specimens without the use of HA. Bonding strength was evaluated by push‐out test, and histomorphometric measurements were made with analysis software to calculate the average value of bone ingrowth. A significantly higher bonding strength was observed for the specimens with HA‐incorporated implant at 3 and 5 weeks, and larger bone ingrowth deep inside the titanium fiber mesh was measured at 3 weeks. Our proposed method has the additional advantage of not requiring a high temperature that may result in changes in characters of HA powder such as phase transition, grain growth, and decomposition. Moreover, this technique of HA powder incorporation without high‐temperature treatment allows the use of several types of metallic fiber mesh, as well as the application to fiber mesh made of organic polymers. We conclude that this simple modification of titanium fiber mesh with HA powder can improve the fixation of implant to bone in the initial stage after operation. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Tissue engineering of articular cartilage using an allograft of cultured chondrocytes in a membrane‐sealed atelocollagen honeycomb‐shaped scaffold (ACHMS scaffold)
Authors: Masuoka Kazunori , Asazuma Takashi , Ishihara Masayuki , Sato Masato , Hattori Hidemi , Ishihara Miya , Yoshihara Yasuo , Matsui Takemi , Takase Bonpei , Kikuchi Makoto , Nemoto Koichi
Published: July 2005

The aim of this study was to investigate with tissue engineering procedures the possibility of using atelocollagen honeycomb‐shaped scaffolds sealed with a membrane (ACHMS scaffold) for the culturing of chondrocytes to repair articular cartilage defects. Chondrocytes from the articular cartilage of Japanese white rabbits were cultured in ACHMS scaffolds to allow a high‐density, three‐dimensional culturing for up to 21 days. Although the DNA content in the scaffold increased at a lower rate than monolayer culturing, scanning electron microscopy data showed that the scaffold was filled with grown chondrocytes and their produced extracellular matrix after 21 days. In addition, glycosaminoglycan (GAG) accumulation in the scaffold culture was at a higher level than the monolayer culture. Cultured cartilage in vitro for 14 days showed enough elasticity and stiffness to be handled in vivo. An articular cartilage defect was initiated in the patellar groove of the femur of rabbits and was subsequently filled with the chondrocyte‐cultured ACHMS scaffold, ACHMS scaffold alone, or nonfilled (control). Three months after the operations, histological analysis showed that only defects inserted with chondrocytes being cultured in ACHMS scaffolds were filled with reparative hyaline cartilage, and thereby highly expressing type II collagen. These results indicate that implantation of allogenic chondrocytes cultured in ACHMS scaffolds may be effective in repairing articular cartilage defects. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Fabrication and evaluation of a new composite composed of tricalcium phosphate, gelatin, and Chinese medicine as a bone substitute
Authors: Yao Chun‐Hsu , Tsai Hung‐Ming , Chen Yueh‐Sheng , Liu Bai‐Shuan
Published: July 2005

This study investigates the biological effects of traditional Chinese medicines on the activities of bone cells using rat bone cells. Then, a mixture of a GGT composite, that is, a novel biodegradable composite containing genipin crosslinked gelatin and tricalcium phosphate, and traditional Chinese medicine (TCM) was prepared as a GGT–TCM composite. A cultured neonatal rat calvarias organ was used to measure the potential of GGT–TCM composite for use in promoting the regeneration of defective bone tissue. The mitochondria activity of the bone cells following exposure to various concentrations of crude extracts of five herbal Chinese medicines was measured by colorimetric assay. Biochemical markers, such as alkaline phosphatase (ALP) and tartrate‐resistant acid phosphatase (TRAP) titers were analyzed to evaluate the activities of bone cells. Finally, we examined the organ culture units, which were maintained in cultured medium for 5 weeks. Morphology of tissue was observed, and the quantitative evaluation of the regenerated bone was determined. In a bone cells culture experiment, adding Cuscuta chinensis Lam. (TCM‐5) to the bone cells culture clearly promoted the proliferation and differentiation of the osteoblasts from their precursor cells; but the reduced amount of TRAP indicated that the medicine significantly inhibited the osteoclasts activities. Opposite bone cell responses were observed when Loranthus parasiticus Merr. (TCM‐3) and Achyranthes bidentata Bl. (TCM‐4) were added to the bone cells culture. Eucommia ulmoides Oliv. (TCM‐1) and Dipsacus asper Wall. (TCM‐2) potentially influence the proliferation and differentiation of the osteoblasts from their precursor cells, but they did not affect the osteoclasts activities. The finding from the organ culture indicated that Chinese medicine effectively increased the rate of tissue regeneration of damaged bones. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Evaluation of different scaffolds for BMP‐2 genetic orthopedic tissue engineering
Authors: Xu X. Leon , Lou Jueren , Tang Tingting , Ng Kenneth Wayman , Zhang Junhui , Yu Chaofeng , Dai Kerong
Published: July 2005

To better understand the effects of scaffold materials for bone morphogenetic protein 2 (BMP‐2) genetic tissue engineering in vivo, several gels, including alginate, collagen, agarose, hyaluronate, fibrin, or Pluronic, were mixed with adenovirus‐mediated human BMP‐2 gene (Adv‐hBMP‐2) transduced bone marrow stromal cells (BMSCs) and injected into the muscles of athymic mice to evaluate the resulting osteogenesis and chondrogenesis. These gel and gene‐transduced BMSC mixtures were also loaded onto β‐TCP/HAP biphasic calcined bone (BCB) and observed under scanning electron microscopy (SEM). In addition, these composite scaffolds were implanted into the subcutaneous site of athymic mice to construct tissue‐engineered bone. After injection, collagen, hyaluronate, or alginate gel mixed with gene‐transduced BMSCs induced more bone formation than a cell suspension in α‐MEM. The agarose‐gene‐transduced BMSC gel was found to contain much more hyaline cartilage. SEM showed the BMSCs could survive in alginate, agarose, and collagen gel in vitro for up to 8 d. After implantation of tissue‐engineered bone, the alginate, collagen, and agarose gel could promote new bone formation within a BCB in vivo. Little or no bone formed after injection of fibrin or Pluronic gel mixed with BMSCs or implantation with BCB. These findings help to elucidate the effects of various scaffold materials for future research in orthopedic tissue engineering using BMP‐2 transduced cells. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Magnetic force‐based mesenchymal stem cell expansion using antibody‐conjugated magnetoliposomes
Authors: Ito Akira , Hibino Eri , Shimizu Kazunori , Kobayashi Takeshi , Yamada Yoichi , Hibi Hideharu , Ueda Minoru , Honda Hiroyuki
Published: July 2005

Recently, there has been an accumulation of evidence indicating that human mesenchymal stem cells (MSCs, multipotent cells resident in the bone marrow) are useful for autologous cell transplantation. However, only small numbers of MSCs have been obtained in bone marrow aspirates. We have developed a novel methodology for enriching and proliferating MSCs from bone marrow aspirates using antibody‐conjugated magnetoliposomes (AMLs). The AMLs are liposomes conjugated to anti‐CD105 antibody (immunoliposomes) and contain magnetite nanoparticles (diameter 10 nm). In the present study, the AMLs were added to a small volume (1 mL) of human bone marrow aspirate. After a 1‐h incubation period, the bone marrow aspirates containing AMLs were seeded into 10‐cm tissue culture dishes, and a disk‐shaped magnet (diameter 2.2 cm; height 1 cm; 4000 Gauss) was positioned under the dish to enrich MSCs by magnetic force. The MSCs proliferated, forming colonies at the site where the magnet was positioned. In contrast, no colonies and very few viable cells were observed in ordinary culture based on plastic‐adherent tendencies of cells without use of AMLs. These results suggest that this AML culture method can rapidly and efficiently expand a small number of MSCs into numbers suitable for clinical application. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
The growth improvement of porcine esophageal smooth muscle cells on collagen‐grafted poly(DL‐lactide‐co‐glycolide) membrane
Authors: Zhu Yabin , Chan‐Park Mary B. , Sin Chian Kerm
Published: July 2005

Synthetic polyester and the extracellular matrix component collagen are among the most widely used materials in tissue engineering. However, the integration of collagen into polyester scaffolds without loss of its biological function is a problem that has not been fully solved. This article investigates the covalent immobilization of collagen onto poly(DL‐lactide‐co‐glycolide) (PLGA) membrane surfaces via a bridge of 1,8‐diaminooctane and with glutaraldehyde as crosslinking agent. X‐ray photoelectron spectroscopy (XPS) and fluorescence measurements confirmed the presence of bonded collagen. The effect of collagen grafting on cell behavior was investigated by comparing collagen‐PLGA with unmodified PLGA sample and tissue culture polystyrene (TCPS) plates by using porcine esophageal smooth muscle cells (ESMC). DNA analysis showed that collagen‐modified PLGA improved the overall proliferation of the ESMCs compared with unmodified PLGA and TCPS plates. Cells seeded on collagen‐modified PLGA also showed a more extended morphology. Thus, we believe that collagen‐modified PLGA shows good potential to be used as a scaffold material for tissue engineering of the esophagus. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Laser‐layered microfabrication of spatially patterned functionalized tissue‐engineering scaffolds
Authors: Mapili Gazell , Lu Yi , Chen Shaochen , Roy Krishnendu
Published: July 2005

Understanding cell behavior inside complex, three‐dimensional (3D) microenvironments with controlled spatiotemporal patterning of physical and biochemical factors would provide significant insights into the basic biology of organ development and tissue functions. One of the fundamental limitations in studying such behavior has been the inability to create patterned microenvironments within 3D scaffold structures. Here a simple, layer‐by‐layer stereolithography (SL) method that can precisely pattern ligands, extracellular‐matrix (ECM) components, and growth factors, as well as controlled release particles inside a single scaffold, has been developed. The process also allows fabrication of predesigned internal architectures and porosities. Photocrosslinkable poly(ethylene glycol) dimethacrylate (PEGDMA) was used as the basic structural component of these microfabricated scaffolds. PEG acrylates, covalently modified with the cell adhesive peptide arginine‐glycine‐aspartic acid (RGD) or the ECM component heparan sulfate, was incorporated within the scaffolds to facilitate cell attachment and to allow spatial sequestration of heparan‐binding growth factors. Fluorescently labeled polymer microparticles and basic fibroblast growth factor (FGF‐2) were chosen to illustrate the capability of SL to spatiotemporally pattern scaffolds. The results demonstrate that a precise, predesigned distribution of single or multiple factors within a single 3D structure can be created, and specific internal architectures can be fabricated. Functionalization of these scaffolds with RGD is demonstrated, and heparan sulfate allows efficient cell attachment and spatial localization of growth factors. Such patterned scaffolds might provide effective systems to study cell behavior in complex microenvironments and could eventually lead to engineering of complex, hybrid tissue structures through predesigned, multilineage differentiation of a single stem‐cell population. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Interleukin‐1‐β gene, but not the interleukin‐1 receptor antagonist gene, is associated with graves' disease
Authors: Chen Rong‐Hsing , Chen Wen‐Chi , Chang Chwen‐Tzuei , Tsai Chang‐Hai , Tsai Fuu‐Jen
Published: July 2005

Interleukin‐1 (IL‐1) is considered to be involved in the pathogenesis of Graves' disease. The aim of this study was to test whether the IL‐1‐β gene promoter region and exon 5 and IL‐1 receptor antagonist (IL‐1Ra) gene intron 2 polymorphisms could be useful genetic markers for susceptibility to Graves' disease. A normal control group of 163 healthy people and another group of 95 patients with Graves' disease were examined. Polymerase chain reaction (PCR) was used to analyze the variable number of tandem repeats (VNTRs) at intron 2 of the IL‐1Ra gene for the polymorphism. PCR‐based restriction analysis was done for the IL‐1‐β gene polymorphisms of the promoter region and exon 5 using endonucleases AvaI and TaqI, respectively. We found significantly increased frequencies of the C/C homozygous genotype (χ2 test, P=0.038; odds ratio (OR)=2.558, 95% confidence interval (CI)=1.205–5.430) and the C allele (χ2 test, P=0.011; OR=1.589, 95% CI=1.094–2.309) in the IL‐1‐β gene promoter (−511 C/T polymorphism) in Graves' disease patients compared to normal controls. There were no significant differences in polymorphisms of IL‐1‐β gene exon 5 and IL‐1Ra gene intron 2 between the patient and normal control groups. A subgroup analysis also demonstrated no association between the severity of the disease and any polymorphism of IL‐1‐related genes. We suggest that the IL‐1‐β gene promoter polymorphism can be used as a genetic marker for susceptibility to Graves' disease. It is worthwhile to study the cytokine genes further because of the association between cytokines and Graves' disease. J. Clin. Lab. Anal. 19:133–138, 2005. © 2005 Wiley‐Liss, Inc.
Development of PCR‐ELISA for the detection of hepatitis B virus x gene expression and clinical application
Authors: Kim Jong‐Wan , Shim Jung‐Hyun , Park Joo‐Won , Jang Won‐Cheol , Chang H.K. , Song Il Han , Baek Sun‐Young , Lee Seok‐Ho , Yoon Do‐Young , Park Sue‐Nie
Published: July 2005

The presence of hepatitis B virus x (HBx) antigen/antibody is known to correlate with the well‐established serological markers of ongoing viral replication in the chronic phase of HBV infection, and strongly suggests that the level and duration of HBx expression may influence the outcome of the chronic infection. In this research, we developed a polymerase chain reaction enzyme‐linked immunosorbent assay (PCR‐ELISA) method for the detection of HBx gene expression. We also investigated its relationship to the progress of the disease in HBV‐related patients. Peripheral blood mononuclear cells (PBMCs) were purely isolated, and reverse transcription‐PCR (RT‐PCR) was performed for improved sensitivity. The PCR products were determined by ELISA, and we investigated the relationship of the proposed method to the clinical status of the patients. The PCR‐ELISA used in this work was found to be at least 100 times more sensitive than the conventional PCR method, and even 8,000‐fold diluted PCR products could be detected. The HBx concentrations significantly differed among control subjects (0.36±0.09, [P<0.01] and patients with chronic hepatitis (1.13±0.34 [P<0.01 compared to control]), liver cirrhosis (LC; 1.37±0.28 [P<0.01 compared to control]), and hepatocellular carcinoma (HCC; 1.48±0.95 [P<0.01 compared to control]). These findings suggest that monitoring of HBx could be useful for early diagnosis and prognosis in patients with chronic HBV infection, LC, and HCC. J. Clin. Lab. Anal. 19:139–145, 2005. © 2005 Wiley‐Liss, Inc.
Novel rapid immunochromatographic test based on an enzyme immunoassay for detecting nucleocapsid antigen in SARS‐associated coronavirus
Authors: Kogaki Hiroyuki , Uchida Yoshiaki , Fujii Nobuyuki , Kurano Yoshihiro , Miyake Kazushige , Kido Yasuji , Kariwa Hiroaki , Takashima Ikuo , Tamashiro Hiko , Ling Ai‐Ee , Okada Masahisa
Published: July 2005

A novel severe acute respiratory syndrome‐associated coronavirus (SARS‐CoV) has been discovered. The detection of both antigens and antibodies in SARS‐CoV from human specimens with suspected SARS plays an important role in preventing infection. We developed a novel rapid immunochromatographic test (RICT) based on the sandwich format enzyme immunoassay (EIA) with an all‐in‐one device for detecting the native nucleocapsid antigen (N‐Ag) of SARS‐CoV using monoclonal antibodies (MoAbs), which we produced by immunizing recombinant N‐Ag to mice. RICT is a qualitative assay for respiratory aspirates and serum specimens. With this assay, a positive result can be judged subjectively by the appearance of a blue line on the device 15 min after the sample is applied. RICT with several pairs of MoAbs showed a high sensitivity for the detection of recombinant N‐Ag as well as viral N‐Ag of SARS‐CoV. rSN122 and rSN21‐2 were the best MoAbs for immobilized antibody and enzyme labeling, respectively. With regard to analytical sensitivity, RICT detected N‐Ag at 31 pg/mL for recombinant N‐Ag, and at 1.99×102 TCID50/mL for SARS‐CoV. The specificity of RICT was 100% when 150 human sera and 50 nasopharyngeal aspirates (NSPs) were used. RICT based on an EIA using the rSN122/rSN21‐2 pair is a sensitive, specific, and reliable rapid assay for detecting N‐Ag in SARS‐CoV treated with either heat or Triton X‐100. J. Clin. Lab. Anal. 19:150–159, 2005. © 2005 Wiley‐Liss, Inc.
Low utility of CYFRA 21‐1 serum levels for diagnosis and follow‐up in bladder cancer patients
Authors: Fatela‐Cantillo Daniel , Fernández‐Suárez Antonio , Menéndez Violeta , Galán Juan Antonio , Filella Xavier
Published: July 2005

We evaluated serum levels of soluble fragments of cytokeratin 19 (CYFRA 21‐1) by immunoassay (ES‐700; Roche Diagnostics, Mannheim, Germany) to assess its usefulness in the diagnosis and follow‐up of bladder cancer. The study included 39 patients with a diagnosis of transitional cell carcinoma (group 1) and 190 patients (group 2) with no evidence of tumor. In group 2, 180 patients had a history of bladder cancer, and 10 had benign prostatic hyperplasia. Significant differences in CYFRA 21‐1 concentrations between groups 1 and 2 (P<0.01) were noted. However, CYFRA 21‐1 levels did not significantly differ between the patients with benign prostatic hyperplasia and those with bladder cancer (P=0.274). CYFRA 21‐1 values were higher in invasive bladder cancer compared to that detected in superficial stages (P=0.011). Setting the optimal cutoff value at 2.5 ng/mL resulted in a sensitivity of 43.6% and a specificity of 82.1%. No statistical differences were found when we compared disease‐free time among the 66 patients with recurrences (30.7 months with levels <2.5 ng/mL vs. 41.2 months with levels >2.5 ng/mL; P=0.248). The risk of recurrence in patients with levels lower than 2.5 ng/mL (0.79) was no different (P=0.097) from that found in patients with higher levels (1.69). CYFRA 21‐1 serum levels do not provide enough sensitivity to justify its application in routine protocols for the detection and follow‐up of bladder cancer. J. Clin. Lab. Anal. 19:167–171, 2005. © 2005 Wiley‐Liss, Inc.
Urinary N‐acetyl‐β‐D‐glucosaminidase (NAG) in lupus nephritis and rheumatoid arthritis
Authors: Erdener Dilek , Aksu Kenan , Biçer İlhan , Doğanavşargil Eker , Kutay Fatma Z.
Published: July 2005

Increased activity of urinary N‐acetyl‐β‐D‐glucosaminidase (NAG) can be used as an early indicator of damage to the tubular epithelium. Systemic lupus erythematosus (SLE) is a multisystem autoimmune rheumatic disease. Nephritis is known as the most serious complication of SLE and the strongest predictor of poor outcome. In this study urinary NAG excretion was investigated in 24 SLE patients with normal renal function (serum creatinine ≤1.2 mg/dL) and the results were compared with those from 26 untreated patients with rheumatoid arthritis (RA) and 27 healthy controls. The SLE patients were divided into two groups according to their urinary total protein levels: group A consisted of 16 patients with ≤3.5 g/day proteinuria, and group B consisted of eight patients with nephrotic‐range proteinuria (>3.5 g/day). Serum and urinary creatinine, total urinary protein levels, and urinary NAG excretion were measured in patients with SLE and RA. In addition, serum C3 and C4 levels were determined in the SLE patients. Renal biopsies were performed in all of the SLE patients. Glomerular lesions were classified according to WHO criteria for lupus nephritis (LN) I–V. The Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) was used to assess disease activity. Urinary NAG excretion was significantly higher in the SLE groups than in the healthy controls (P<0.001). In urinary NAG excretion there was also significant difference between SLE groups and RA patients (P<0.001). However, there was no significant difference in NAG excretion between the RA and control groups (P=0.062). Urinary NAG excretion was significantly higher (P<0.05) in group B compared to group A. There were no differences in SLEDAI scores, ages, and serum creatinine levels between study groups (P=0.601, P=0.285, P=0.669, respectively). Elevated SLEDAI values and hypocomplementemia were detected more often in younger patients (P<0.010, r=–0.529 and P<0.010, r=–0.569, respectively). There was a strong positive correlation between proteinuria and urinary NAG activity (P<0.001, r=0.759). These results suggest that the determination of urinary NAG activity may be a useful supplement to the routine biochemical analysis performed on the urine in cases of SLE. J. Clin. Lab. Anal. 19:172–176, 2005. © 2005 Wiley‐Liss, Inc.
Policy entrepreneurship for poverty reduction: bridging research and policy in international development
Authors: Court Julius , Maxwell Simon
Published: July 2005

Bridging research and policy is a topic of growing practical and scholarly interest in both North and South. Contributions by four experienced practitioners and in four papers by researchers illustrate the value of existing frameworks and add four new lessons: the need for donors and research foundations to foster research capacity and to protect it from political interference; the need for researchers to use detailed case material in order to inform high‐level policy debates within and across national boundaries, often by working in cross‐country teams; the importance of presenting research results in such a way that they cannot be over‐simplified; and the value of creating alliances between researchers and civil society advocacy groups. Copyright © 2005 John Wiley & Sons, Ltd.
Research, policy and practice: why developing countries are different
Authors: Young John
Published: July 2005

Better utilization of research and evidence in development policy and practice can help save lives, reduce poverty and improve the quality of life. However, there is limited systematic understanding of the links between research and policy in international development. The paper reviews existing literature and proposes an analytical framework with four key arenas: external influences, political context, evidence and links. Based on the findings of stakeholder workshops in developing countries around the world, the paper identifies four key issues that characterize many developing countries. These are: (i) troubled political contexts; (ii) problems of research supply; (iii) external interference; and (iv) the emergence of civil society as a key player. Despite these challenges, two institutional models seem to be particularly effective: (i) think tanks and (ii) regional networks. Copyright © 2005 John Wiley & Sons, Ltd.
Poverty and economic policy: what happens when researchers disagree?
Authors: Sumner Andrew , Tiwari Meera
Published: July 2005

This paper is concerned with disagreements between researchers over economic policy and poverty and the implications for policy makers. It sets out to show that on three selected policy questions the ‘conventional wisdom’ is in fact highly contested. It then discusses why this might be and what the implications are for policy makers. The three policy questions chosen are: Is growth good for the poor? Is public expenditure good for the poor? And is globalization good for the poor? It is argued that policy makers need some criteria to judge the ‘appropriateness’ of competing ‘evidence’ in a particular context. Some such criteria are tentatively proposed. Copyright © 2005 John Wiley & Sons, Ltd.
Bridging research and policy on education, training and their enabling environments
Authors: King Kenneth , Palmer Robert , Hayman Rachel
Published: July 2005

This paper revisits the research origins of one well‐known claim which has been used in policy documents over the past 25 years, namely that four years of education increase agricultural productivity. The oversimplification of the original research findings has influenced funding patterns of aid agencies, leading to a concentration on primary education in Africa. While this demonstrates a ‘successful’ case of research leading to policy change, it also highlights the way in which simple policy ‘narratives’ can result in inappropriate policy positions. We argue that policy positions on this link between education and the environment are also based on commonsense without sufficient research into what appears to be not a one‐way but a two‐way inter‐relationship between quality education and training and the wider environment. Copyright © 2005 John Wiley & Sons, Ltd.
Sex differences in glycolysis during brief, intense isometric contractions
Authors: Russ David W. , Lanza Ian R. , Rothman Douglas , Kent‐Braun Jane A.
Published: July 2005

We have previously observed less muscle fatigue in women than men under conditions of intact circulation, but similar fatigue across the sexes during local ischemia. Thus, we hypothesized that women utilize their aerobic metabolic pathways to a greater extent than do men. To test this hypothesis, we examined the extent to which different pathways of intramuscular adenosine triphosphate (ATP) production were utilized by men and women during maximal voluntary isometric contractions. Force production during 15‐s and 60‐s contractions were recorded in parallel sessions. In one session, central activation was assessed with electrical stimulation. In the other, phosphorus magnetic resonance spectroscopy was used to quantify muscle oxidative capacity, and the contributions of glycolysis and oxidative phosphorylation to ATP synthesis during the 60‐s contraction. Fatigue and central activation were similar in men and women during both the 15‐s and 60‐s contractions. The rate constants of phosphocreatine recovery following the 15‐s contraction were similar in men and women, indicating similar oxidative capacities. Men exhibited greater acidosis and peak glycolytic rates compared with women during the 60‐s contraction, with no differences observed in creatine kinase flux or the percent of oxidative capacity utilized. We conclude that men exhibit greater in vivo glycolysis during brief, intense isometric contractions. Although this metabolic difference did not contribute to any observable differences in fatigue in the present study, these results highlight a potentially important mechanism to explain sex‐related differences in muscle function. Muscle Nerve, 2005
A model of muscle atrophy using cast immobilization in mice
Authors: Frimel Tiffany N. , Kapadia Fatema , Gaidosh Gabriel S. , Li Ye , Walter Glenn A. , Vandenborne Krista
Published: July 2005

We describe a new cast‐immobilization protocol to induce muscle atrophy in the lower hindlimb muscles of mice. Bilateral cast immobilization for 2 weeks in a shortened position resulted in a significant loss of muscle size and strength in the soleus and extensor digitorum longus. The availability of a model of cast immobilization in mice may benefit future studies targeting genetic or cell therapy interventions of muscle atrophy in transgenic and mutant mice strains. Muscle Nerve, 2005