Chemical Research in Chinese Universities

Content of Chemical Research in Chinese Universities Vol.24 No.4(2008)

2008, 24(4): 0-0. doi:

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Synthesis and Characterization of a One-dimensional Coordination Polymer Generated from Unsymmetrical Bridging Organosulfur Ligand

WANG Lei , ZHANG Hui , DONG Wen-jun , SHI Zhan , FENG Shou-hua

2008, 24(4): 389-391. doi:

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A new one-dimensional(1D) coordination polymer [Zn(MMTA)₂]_n(MMTA=5-mercapto-1-methyl-tetrazole) was synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction. This compound crystallizes in the monoclinic space group C2/c, with cell parameters: a=1.4938(7) nm, b=1.3599(5) nm, c=1.2180(4) nm, β=120.84(3)˚, V=2.1243(2) nm³, and Z=8. The deprotonated HMMTA molecule as a μ₂-ligand links the zinc center, forming 1D chains, which are futher linked by weak C―H···N hydrogen bonds, forming a three-dimensional supramolecular framework. The compound exhibits intense photoluminescence at room temperature. On the basis of the results of TG/DTA analyses, the structure is thermally stable up to ~280 ºC.

Two New Iron Coordination Polymers Based on Fe-pyta Chains Incorporating Pyridine-2,4,6-tricarboxylate

CHEN Zi-yun , PENG Meng-xia

2008, 24(4): 392-395. doi:

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Reaction of FeCl₂·6H₂O, pyridine-2,4,6-tricarboxylic acid(H₃pyta) and NaOH in the hydrothermal system at 185 oC resulted in the formation of 1D coordination polymer[Fe(Hpyta)(H₂O)₂](1) based on Fe-Hpyta chains. When the abpt[abpt=4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network (H₂bpt)[Fe(pyta)(H₂O)₂]·4H₂O(2) was obtained. The framework was constructed with negative (Fe-pyta)⁻ chains and the positive H₂bpt⁺ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490(5) nm, b=0.9008(4) nm, c=1.0058(5) nm, β=107.254(9)º, V=0.9942(8) nm³, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392(11) nm, b=0.96027(11) nm, c=1.55540(18) nm, α=73.558(2)º, β= 86.126(2)º, γ= 68.745(2)º, V=1.2059(2) nm³ and Z=2.

Synthesis and Crystal Structure of a Complex of Melamine with Benzoic Acid

ZHANG Xiu-lian

2008, 24(4): 396-400. doi:

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A new complex of melamine(MA) with benzoic acid(HBA) was prepared, affording [(HMA⁺)(BA⁻)]·2H₂O. Each HBA molecule is deprotonated and one triazine nitrogen atom of MA is protonated. The adjacent HMA⁺ cations are related via an inverse center to form ribbons with a pair of N―H···N hydrogen bonds. COO⁻ groups of BA⁻ anions are hydrogen bonded to alternate sides of the (HMA⁺)_∞ ribbons to generate indention 1D tapes, which are extended into a 3D structure via N―H···O⁻ and N―H···OW hydrogen bonds and π···π stacking interactions. Predominant patterns of the hydrogen bond present in the complex are anion/water and amino/water tape structures. The hydrogen-bonding patterns consist of alternate 6, 10-membered rings sharing two edges. Infrared(IR) spectroscopy conforms that proton transfer has taken place in the complex.

Synthesis, Characterization, and DNA Binding Properties of Dinuclear Copper(II) Complex [Cu₂(TATP)₂(L-Leu)₂(ClO₄)₂]₂·2H₂O

GU Qin , LIN Qing-bin , LIU Ying-ju , LE Xue-yi , FENG Xiao-long

2008, 24(4): 401-406. doi:

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A dinuclear copper(II) complex [Cu₂(TATP)₂(L-Leu)₂(ClO₄)₂]₂·2H₂O was synthesized and characterized, where, TATP=1,4,8,9-tetraazatriphenylene, and L-Leu=L-leucinate. The complex was crystallized in the triclinic space group P1, with two independent molecules in a unit cell. Two Cu(II) ions in each complex [Cu₂(TATP)₂(L-Leu)₂(ClO₄)₂] molecule were found to be in different coordination geometries, i.e., Cu2 or Cu4 of a distorted square-pyramidal geometry coordinated with two nitrogens of TATP, the amino nitrogen and one carboxylate oxygen of L-Leu and one oxygen of perchlorate, and Cu1 or Cu3 with an octahedral geometry coordinated with the above stated similar coordinated atoms, and another carboxylate oxygen of L-Leu coordinating to Cu2 or Cu4. The complex can interact with CT-DNA by an intercalative mode and cleave pBR322 DNA in the presence of ascorbate.

Preparation of Copper Phthalocyanine Crystals Using Solvothermal Synthesis

XIA Dao-cheng , LI Wan-cheng , WANG Xu , YU Shu-kun , FAN Cui-xiang5 , MA Chun-yu , CHENG Chuan-hui , FAN Zhao-qi , DU Guo-tong , CONG Fang-di , DU Xi-guang

2008, 24(4): 407-410. doi:

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A novel solvothermal synthesis method for the direct growth of β-form crystals of copper phthalocyanine(CuPc) is presented in this article. With quinoline as solvent, crystals were grown after cooling the reaction mixture of 1,3-diiminoisoindoline and copper oxide, heated for 9 h at 270 °C, to room temperature in an autoclave. These high quality crystals were suitable for characterization measurements. The single-crystal diffraction data show a monoclinic system unit cell: a=1.4668(3) nm, b=0.48109(10) nm, c=1.9515(7) nm, α=90°, β=121.04(2)°, γ=90°, where the corresponding cell volume is 1.17991 nm³. Needle-like single crystals of CuPc up to 10.5 mm in length were obtained. The influences of different temperatures, reaction time and solvent volume on the crystal yields were also discussed. Optimum reaction conditions were 10 mL of quinoline, at 270 °C for 8 h.

Biological Fingerprinting Analysis of Interaction Between Taxoids in Taxus and Microtubule Protein by Microdialysis Coupled with High-performance Liquid Chromatography/Mass Spectrometry for Screening Antimicrotubule Agents

LEI Xiao-yuan , KONG Liang , SU Xing-ye , GUO Ming , ZOU Han-fa

2008, 24(4): 411-419. doi:

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Some natural products, such as traditional Chinese medicines(TCMs), contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography (HPLC) is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold & Zucc(Taxus) to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin III(10-DAB), cephalomannine and 7-epi-10-deacetyltaxol (7-epi-10-DAT) based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin III and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.

Simultaneous LC-MS/MS Determination of Danshensu and Paeoniflorin for Permeability Studies in Caco-2 Intestinal Absorption Model

LIU Li , ZHAO Xiao-ping , ZHU Di-feng , CHENG Yi-yu , QU Hai-bin

2008, 24(4): 420-426. doi:

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A high sensitive method based on liquid chromatography tandem mass spectrometry(LC-MS/MS) was developed and validated for the study of permeability of danshensu(DS) and paeoniflorin(PF) in Caco-2 intestinal absorption model. The DS and PF were extracted from cell culture by vacuum-lyophilizing and then separated on a Zorbax Stable Bond C₁₈ column with 0.1% acetic acid aqueous solution and methanol as mobile phase. Detection was carried out by negative electrospray ionization(ESI⁻) with selected reaction monitoring(SRM) mode. The apparent permeability coefficients(P_app) of DS and PF in Caco-2 cell medium were calculated and the effects of verapamil on the coefficients P_app of the two test compounds were also illustrated. The permeability of PF was much better than that of DS when the two compounds were administrated individually. Co-administration of DS and PF led to the decrease of the transport from apical side to basolateral side for both the compounds. However, the transport in the contrary direction were accelerated. It was also observed that verapamil could accelerate the transport of the test compounds from apical side to basolateral side. However, the absorption-enhanced effect of verapamil was attenuated when DS and PF were co-administrated. These observations suggest that both passive diffusion and active efflux involved in P-gp would effect the passage of DS and PF across Caco-2 cell monolayer. At the same time, the co-administration of DS and PF to an alteration of transport behavior, which suggests that the interaction must be taken into account when 'n-in-one' samples were used in Caco-2 intestinal model.

Cytotoxic Diarylheptanoids from Pericarps of Juglans Cathayensis Dode

LI Yi-xiu, RUAN Han-li, ZHOU Xue-feng, ZHANG Yong-hui, PI Hui-fang , WU Ji-zhou

2008, 24(4): 427-429. doi:

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A novel diarylheptanoid, named Jugcathanin(1), along with two known diarylheptanoids(2,3), were isolated from the fresh pericarps of Juglans Cathayensis Dode. A known triterpene(4) and a known aphthaoquinone(5) were also isolated from the plant. Their structures were elucidated on the basis of spectroscopic studies. All the compounds exhibited moderate cytotoxicities against human Hela, HepG2, and HL-60 cell lines.

Detecting and Identifying in vivo Metabolites of Brodimoprim via LC/ESI-MS with Data-dependent Scanning

LIN Yan-ping , SI Duan-yun , LIU Chang-xiao

2008, 24(4): 430-436. doi:

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The present article covers a simple approach to detect and subsequently identify in vivo metabolites of brodimoprim, using high performance liquid chromatography coupled to ion trap mass spectrometer(LC/ESI-MS), which is based on a data-dependent acquisition of isotope ions and result verified by full scan mass spectrum. The distinguished advantage of data-dependent scan is rapidness because it requires minimum sample preparation, and all the necessary data can be obtained in one chromatographic run. In addition, it is highly sensitive and selective, allowing detection of trace metabolites even in the presence of complex biomatrix. As a result, four phase-I(M1―M4) and four Phase-II(M5―M8) metabolites of brodimoprim were identified in urine after the oral administration of brodimoprim to Wistar rats. Their chemical structures were proposed based on the interpretation of their CID fragmentation characterizations and the metabolic pathway was exhibited in this article.

Efficient Synthesis of 3,5,6,7-Tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-ones

LIU Ming-guo , ZHONG Ying , DING Ming-wu

2008, 24(4): 437-440. doi:

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The title compounds 3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-4-ones(6) were syn- thesized by base catalytic reactions of secondary amines with carbodiimides 4, which were obtained from the aza-Wittig reaction of iminophosphoranes(3) with aromatic isocyanates.

Chiral Separation of Spiro-compounds and Determination Configuration

LIANG Ya, GUO Jing-jing, LIU Xiu-ming , WEI Rong-bao

2008, 24(4): 441-444. doi:

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Chiral spirocyclic compounds have attracted the attention of scholars and scientists owing to their potential applications in the pharmaceutical industry as either active pharmaceutical ingredients, catalysts in synthesizing active enantiomers, or as surface modifiers on silica particles to resolve entantiomers. In this study, five spiro compounds of 3,9-diphenyl-2,4,8,10-tetraoxaspiro[5.5]-undecane(1), 3,9-(4-methoxyphenyl)-2,4,8,10-tetraoxaspiro[5.5]-undecane(2), 3,9-(4-methylphenyl)-2,4,8,10-tetraoxaspiro[5.5]-undecane(3), 4,4’-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)diben- zoic acid(4) and 3,9-di(4-formyl-phenyl)-2,4,8,10-tetraoxa-spiro[5.5]-undecane(5) were synthesized by grinding pentaerythritol with benzaldehyde, 4-methoxybenzaldehyde, 4-methylbenzaldehyde, 4-carboxybenzaldehyde or terephthalaldehyde monoacetal in the presence of InBr₃ under solvent-free conditions. A normal phase HPLC method was successfully developed to resolve entantiomers of compounds 1―5 on a chiral column. Specific optical rotation of R or S entantiomers(1) was determined and the corresponding configurations were proposed based on Lowe’s rule.

Synthesis of 3-Benzyloxy-6-methyl-7-methoxyphenanthrene-9-carboxaldehyde with Utilize Intramolecular Heck Reaction as the Key Step

SONG Yan-ling, , ZHAI Xin , SUN Zhi-feng , KIM Sang-hee , GONG Ping

2008, 24(4): 445-448. doi:

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The substituted phenanthrene-9-carboxyaldehydes are very important intermediates for the syntheses of phenanthroindolizidine and phenanthroquinolizidine alkaloids. The novel title compound was prepared from the reaction of 5 steps starting from the condensation of 3-methoxyl-4-methyl-phenylacetic acid and 4-(benzyloxy)-2-iodo- benzaldehyde, followed by esterification, cyclization, reduction, and oxidation. A new method for the preparation of phenanthrene ring via palladium-catalyzed intramolecular Heck reaction was described. The title compound was characterized by IR, ¹H NMR, ¹³C NMR, elemental analysis, and MS.

Intercalation, Cytotoxicity, and Molecular Modeling of Acenaphtho[1,2-b]pyrrole Chromophores as a New Family of Antitumor Agents

ZHANG Zhi-chao , ZHANG Jing , YUAN Chun-li , WU Gui-ye, , QIAN Xu-hong,5

2008, 24(4): 449-453. doi:

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To explore new platform for DNA intercalation and potent antitumor agent, a series of 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid esters chromophores has been studied. Their intercalation geometries with DNA were revealed through absorption titration, SYBR Green-DNA melt curve, circular dichroism(CD), and docking studies. It was identified that some of the compounds could intercalate into DNA along their long axis parallel to the base-pair long axis, making right-handed B form DNA transform to A-like conformation. Their binding potency varied with the different steric hindrance. Their cytotoxicity(IC₅₀) against MCF-7 cells was found to range between 1.3 to 40.9 µmol/L by MTT assay. Interestingly, the IC₅₀ values did not show any obvious correlation to their binding constants with DNA. The chromophore with a carboxyl group exhibited the most potency of intercalating DNA and could be the promising precursor for the future intercalator for DNA, while the bromide demonstrated the highest cytotoxic activity in this series of compounds.

Synthesis, Characterization and Antibacterial Activity of New 5-Aryl Pyrazole Oxime Ester Derivatives

LIU Xin-hua , ZHI Li-ping , SONG Bao-an , XU Hong-li

2008, 24(4): 454-458. doi:

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Eleven new 1-{5-[4-(benzyloxy)phenyl]-3-methyl-4,5-dihydropyrazol-1-yl} oxime ester derivatives were synthesized and characterized by elemental analysis, HRMS, ¹H NMR data. All the compounds were screened for their antibacterial potential in vitro against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The results indicate that compounds 8c and 8f possess potent activity with the minimum inhibitory concentrations(MIC) of 1.562―3.125 μg/mL against all the four bacteria. Compounds 8c, 8e and 8f show moderate inhibition against the DNA gyrase(IC₅₀=1.9―2.5 µg/mL). On the basis of the biological activities, structure-activity relationship was discussed.

Transferring CdTe Nanoparticles from Liquid Phase to Polyvinylpyrrolidone Nanofibers by Electrospinning and Detecting Its Photoluminescence Property

WANG Shu-gang, YANG Qing-biao, BAI Jie, SONG Yan, ZHANG Chao-qun , LI Yao-xian

2008, 24(4): 459-463. doi:

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The major aim of this work was to synthesize thio-stabilized CdTe nanoparticles(NPs) in an aqueous solution, which was then enwrapped with cetyltrimethylammonium bromide(CTAB), and finally transferred to the polyvinylpyrrolidone(PVP) matrix by electrospinning. The PVP nanofibers containing CdTe NPs were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM), to observe the morphology of the nanofibers and the distribution of CdTe NPs. The selective area electronic diffraction(SAED) pattern verified that CdTe NPs were cubic lattice. The photoluminescence(PL) spectrum indicated that CdTe NPs existed in an optical style in PVP nanofibers. Moreover, X-ray photoelectron spectra(XPS) revealed that thiol-stabilized CdTe NPs were enwrapped by CTAB, and PVP acted as a dispersant in the process of electrospinning.

Biomimetic Decarboxylation of Carboxylic Acids with PhI(OAc)₂ Catalyzed by Manganese Porphyrin [Mn(TPP)OAc]

GHOLAM REZA Karimipour , ROXANA Ahmadpour

2008, 24(4): 464-468. doi:

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Manganese(III) meso-tetraphenylporphyrin acetate [Mn(TPP)OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with (diacetoxyiodo)benzene [PhI(OAc)₂] in CH₂Cl₂-H₂O(95:5, volume ratio). The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn(TPP)OAc. In the former case, the formation of carbonyl products was complete within just a few minutes with >97% selectivities, and no further oxidation of the produced aldehydes was achieved under these catalytic conditions. This method provides a benign procedure owing to the utilization of low toxic(diacetoxyiodo) benzene, biologically relevant manganese porphyrins, and carboxylic acids.

First Total Synthesis of Hyacinthacine A₆ from the Protected Derivative of Polyhydroxylated Pyrrolidine

ZHANG Tao-xiang, ZHOU Ling , CAO Xiao-ping

2008, 24(4): 469-472. doi:

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(1S,2R,3R,5R,7aR)-1,2-Dihydroxy-3-hydroxymethyl-5-methylpyrrolizidine(hyacinthacine A₆, 1) was synthesized by Wittig’s methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the internal reductive amination process of the resulting α,β-unsaturated ketone 7, and total deprotection.

Synthesis of 4′-Spironucleoside via Radical Translocation Cyclization Reaction

DANG Shao-feng, SUN Jing-bo, XU Xian-xiu, WANG Pei , WU Jin-chang

2008, 24(4): 473-476. doi:

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A novel synthetic strategy for the construction of 4′-spironucleosides via cascade radical translocation cyclization of N-allyl-N-(2′-bromophenyl) amide moiety of 5′-carboxylic nucleosides and the N-propynyl analogues is described. The conformationally restricted nucleosides herein synthesized are of potentially biological interests.

Design, Synthesis and Biological Activity of Ethyl 2-(N-Substituted-arylsulfonamido)-2-oxoacetate

WANG Bao-lei, WU Jing, HE Feng-qi, LI Yong-hong , LI Zheng-ming

2008, 24(4): 477-480. doi:

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Thirteen new ethyl 2-(N-substituted-arylsulfonamido)-2-oxoacetates(3a—3m), based on the structure of Ketol-acid reductoisomerase(KARI) inhibitor IpOHA, were designed and synthesized. Their structures were established on the basis of ¹H NMR, IR, MS, and elemental analyses. The bioassay result reveals that the structural changes from hydroxyl group on the N atom of IpOHA to arylsulfonyl groups does not enhance the inhibitory activity of the compounds to KARI in vitro. Compounds 3c, 3h, 3k, and 3m are more effective than IpOHA against the monocotyledonous barnygrass at 100 μg/mL in herbicidal tests.

Inhibition of Growth of Human Ileocecal Adenocarcinoma Cells HCT-8 and Inducing Apoptosis by Different RGD-containing Peptides

WANG Hua , YANG Shao-juan , GAO Shuo-hui , HUANG Yi-bing , LI Jing , CAI Ming-jun , XU Li , ZHANG Xue-zhong

2008, 24(4): 481-486. doi:

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Human ileocecal adenocarcinoma cells HCT-8 were treated with RGD-containing cellular adhesion peptides including RGD, RGD(NH₂)₂(i.e., RGE-NH₂), RGDS, and RGDS-NH₂. MTT assay was prepared to examine their inhibiting effects on HCT-8 cells after treatment. The methods including Haematoxylin and Eosin(HE) staining, transmission electron microscopy(TEM), immunohistochemistry, flow cytometry, and Reverse Transcription- Polymerase Chain Reaction(RT-PCR) were used to observe the morphology of the apoptotic cells and analyze the mechanism of apoptosis. The experimental results indicate that RGD-containing cellular adhesion peptides can inhibit the growth and proliferation of tumor HCT-8 cells in a dose-dependent manner and induce the apoptosis of HCT-8 cells. At the same time, the high conservative property of RGD was confirmed again.

Synthesis of Codon-optimized Human Interleukin-18 Gene by Combination of Chemical and Enzymatic Method

GAO Chao-hui , SHI Xiao-yue , HOU Xin-tong , MENG Qing-fan , Zhang Ying-jiu , TENG Li-rong

2008, 24(4): 487-490. doi:

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According to the amino acid sequence and codon preference of E. coli, the human interleukin-18(IL-18) gene was optimized to avoid the rare codons. The total length of the synthesized gene is 571 bp; 18 oligonucleotides, DNA fragments were designed and synthesized by the phosphoramidite four-step chemical method. The whole DNA sequence was synthesized by a one-step total gene synthesis method, and then inserted in pUC18 vector. Five positive clones identified by blue-white colony screening were sent to Shanghai Sangon Biological Engineering Technology and Service Co., Ltd. for sequencing. The sequencing result shows that one clone contained the complete correct gene in all the five positive clones.

Inhibition of Ampicillin-resistance in Bacteria by Modified DNAzymes

CHEN Fei , LI Zhe , YANG Shuo , WANG Rui-jian , LIU Bin , SONG Yu-ming , SUN Yan-hong , HAO Dong-yun , WANG Xiao-ping

2008, 24(4): 491-495. doi:

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To overcome ampicillin-resistance of bacteria which is believed to attribute their endogenous β-lactamase, we designed three 10-23 DNAzymes(Dz₁, Dz₂, Dz₃) targeting the coding region of β-lactamase mRNA and examined their inhibitory capabilities of the ampicillin-resistance of TEM-1 and TEM-3 bacteria. Dz₁ was a traditional 10-23 DNAzyme, Dz₂ was the mutant of Dz₁ by addition of the protected nucleotide to each arm of the enzyme, and Dz₃ was a mutant of Dz₁ at antisense arms of which phosphorothioate modifications were made. Kinetic analysis, bacterial growth, and β-lactamase activity measurement showed that all the three DNAzymes worked efficiently in vitro and in vivo. A 9 hours bacterial growth inhibition test showed that the inhibition rates of TEM-1 bacteria by Dz₁, Dz₂, and Dz₃ were 27%, 50%, and 29%, respectively. In addition, the inhibition rates of TEM-3 bacteria by those three DNAzymes were found to be 49%, 58%, and 45%, respectively. The current findings suggest that DNAzymes may become potential candidates of alternative inhibitors for bacteria drug-resistance.

Synthesis and Evaluation of Nicotinoylamino Acid Compounds as Radiosensitizer

QIN Zhi-zhong , ZHANG Feng-bao , JIANG Tie-nan , LI Mei-jia , WANG Rong-xian , LI Yi-liang

2008, 24(4): 496-500. doi:

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Nicotinoylamino acid compounds 4, 5, 9a, 9b, 9c, 10a and 10b were synthesized with nicotinoyl chloride or nicotinoyl azide as acetylating agents of amino acid esters or amino acids. The compounds were tested for their radiosensitizing activity in Leukemia cell line(L₁₂₁₀) and compared with nicotinamide; among them, compounds 9a and 9c showed significant radiosensitizing effects, the sensitizer enhancement ratio(SER) was 1.64 and 1.58, respectively, while nicotinamide did not show good radiosensitizing effect under the same conditions. Compound 9c was alone tested for radiosensitization in LA 795 cell-bearing T-739 mice, or hyperthermia and breathing carbogen(5%CO₂+95%O₂) were together tested for radiosensitization. The results showed that radiation-induced growth delay was enhanced by 9c alone or by the combination of hypertheimia and carbogen. The tumor-bearing mice were irradiated locally by total 10 Gy, and the tumors grew to three times that of the original volume in an average of 5.8 d. The mice were given i.p. compound 9c at 1000 mg/kg 60 min before irradiation and treated at 43 °C for 30 min after irradiation or treated with breathing carbogen for 5 min before radiation or with hyperthmia(43 °C) for 30 min after irradiation; the time required for the tumor to grow to three times the orginal volume was in an average of 12.9 and 13 d, respectively.

Effect of β Radiation on Bcl-2 and Bax Expressions in Benign Prostate Hyperplasia Tissues

MA Qing-jie , GAO Shi , ZHAO Jie , GU Xin-quan , CAI Shan-yu , ZHAO Guo-qing

2008, 24(4): 501-504. doi:

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The authors chose specimens from nine normal prostate tissues(NP group), 15 benign prostate hyperplasia(BPH) prostates(BPH group), and 35 BPH prostates that had been treated with ⁹⁰Sr/⁹⁰Y Prostatic Hyperplasia Applicator(exposure group). The expressions of bcl-2 and bax in stroma and epithelia of prostate tissues were demonstrated by means of immunohistochemical staining, and the staining positive rate was semiquantatively determined, so as to observe the expression of bcl-2 and bax genes in the prostate tissues of normal individuals and BPH patients, before and after β radiation, and to evaluate the influence of β radiation on bcl-2 and bax expressions. The expressions of gene bcl-2 in the prostate epithelia of NP and BPH are significantly higher than those in the prostate stroma(P<0.01). However, the expressions of bcl-2 in the prostate epithelia and stroma of the BPH group are obviously higher than those in the NP group(P<0.01). The expression of gene bax in the prostate epithelia of the NP group is higher than that in the BPH group(P<0.05). However, bcl-2 expressions in the prostate epithelia and stroma of the BPH group are significantly higher than the bax expressions(P<0.01). Compared with those of the NP group, the expressions of bcl-2 in the prostate epithelia and stroma of the exposure group decrease remarkably, even as the expressions of the bax notably increase(P<0.01). Thus, the administration of β radiation can remarkably affect bcl-2 and bax gene expressions, to regulate cell apoptosis, in the prostate tissues of BPH.

Establishment of a Tumor-bearing Mouse Model Stably Expressing EGFP Labeled Human MUC1 VNTRs

ZHANG Shu-zi, ZHANG Hai-hong, ZHANG Wa, SHI He-liang, YU Xiang-hui, KONG Wei , LI Wei

2008, 24(4): 505-510. doi:

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Two eukaryotic vectors expressing 9 tandem repeats of human MUC1(VNTR), VR1012-VNTR, and pEGFP-VNTR, were constructed by cloning VNTR gene into VR1012 and pEGFP, respectively. VNTR stably expressing murine Lewis lung carcinoma(LLC) cell line(VNTR⁺ LLC) was established by Lipofectamine-mediated transfection of pEGFP-VNTR into LLC cells. The EGFP expression was observed under a fluorescent microscope and VNTR expression in VNTR⁺ LLC cells was confirmed by means of Western blotting. A syngenic graft tumor model was generated by subcutaneous injection of VNTR+ LLC cells into C57/BL6 mice and tumor size increased rapidly with time and in a cell number dependent manner. VNTR mRNA expression in the tumor formed was confirmed by RT-PCR. After the third immunization mice were challenged subcutaneously with 5×10⁵ VNTR⁺ LLC cells, a significant reduction of subcutaneous tumor growth was observed in the groups immunized with VNTR plasmid DNA compared with that in the groups immunized with the vector DNA alone. Thus, the suppression of subcutaneous tumor was antigen-specific. This model is useful for the development of tumor vaccines targeting MUCI VNTRs.

Impedance Studies of Spinel LiMn₂O₄ Electrode/electrolyte Interfaces

ZHUANG Quan-chao , FAN Xiao-yong , XU Jin-mei , WEI Guo-zhen , DONG Quan-feng , SUN Shi-gang

2008, 24(4): 511-515. doi:

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The formation process of solid electrolyte interphase(SEI) film on spinel LiMn₂O₄ electrode surface was studied by electrochemical impedance spectroscopy(EIS) during the initial storage in 1 mol/L LiPF₆-EC:DMC:DEC electrolyte and in the subsequent first charge-discharge cycle. It has been demonstrated that the SEI film thickness increased with the increase of storage time，and spontaneous reactions occurring between spinel LiMn₂O₄ electrode and electrolyte can be prevented by the SEI film. In the first charge-discharge cycle succeeding the storage, the electrolyte oxidation coupled with Li-ion insertion is evidenced as the main origin to increase the resistance of SEI film. The results also confirm that the variations of the charge transfer resistance(R_ct) with the electrode potential(E) can be well described using a classical equation.

Relative Responses of Noble Gases Using a Pulsed Discharge Helium Photoionization Detector: Theoretical Calculation and Experimental Determination

ZHANG Hai-tao , WU Di , ZHANG Li-xing

2008, 24(4): 516-519. doi:

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The relative response factors(RRFs) for noble gas(Ng) were determined on a pulsed discharge helium photoionization detector. Using ab initio method, the atomic orbitals of noble gas were calculated and used to determine the number of ionizable electrons on the basis of the continuous emission of He₂. The molar responses of noble gases is well correlated with the number of ionizable electrons.

Theoretical Studies on the Iodine-catalyzed Nucleophilic Addition of Acetone with Five-membered Heterocycles

WANG Yan-hua, LI Li , CHEN Xue-song

2008, 24(4): 520-524. doi:

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The iodine-catalyzed nucleophilic addition reactions of pyrrole, furan, or thiophene with acetone were studied in gas and solvent by the density functional theory at the level of Lanl2DZ*. It was seen that the halogen bond between iodine and carbonyl oxygen appeared to have an important catalytic effect on such reactions, and the first iodine molecule maximally diminished the barrier height by 41 kJ/mol, while the second iodine molecule could not improve such reactions largely. It was concluded that the C2-addition was generally more favorable than the C3-addition for the three heterocycles; however, iodine considerably more effectively catalyzed the C3-addition than the C2-addition for pyrrole. It was also revealed by PCM calculation that the iodine-catalyzed nucleophilic additions occurred more easily in solvent than in gas, which explained the experiment performed by Bandgar et al..

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