DNA adduction with nicotine-derived nitrosamine, 4-(methylnitrosamino)-1-(3- pyridy1)-1 -butanone (NNK) in mice at doses equivalent to human exposure has been studied using 14C-label by accelerator mass spectrometry(A...DNA adduction with nicotine-derived nitrosamine, 4-(methylnitrosamino)-1-(3- pyridy1)-1 -butanone (NNK) in mice at doses equivalent to human exposure has been studied using 14C-label by accelerator mass spectrometry(AMS). A detection limit of DNA adducts of 1 adduct Per 1010 nucleotides has been achieved. This sensitivity of AMS measurement is 3 or more orders of magnitude improved than that of radioimmunoassay.Formation of DNA adducts is linearly dependent on dose down to an exposure of 100 ng Per kg of body weight .The ultimate cheeical form of carcinogen NNK binding to DNA is speculated.展开更多
目的评价无托槽隐形矫治器远中移动成年患者上颌磨牙的临床疗效,以提高正畸医生对疗效的预估性。方法检索Web of Science、The Cochrane Library、Embase、Pubmed、万方数据库、知网数据库、维普数据库公开发表的隐形矫治器远移成年患...目的评价无托槽隐形矫治器远中移动成年患者上颌磨牙的临床疗效,以提高正畸医生对疗效的预估性。方法检索Web of Science、The Cochrane Library、Embase、Pubmed、万方数据库、知网数据库、维普数据库公开发表的隐形矫治器远移成年患者上颌磨牙疗效的研究。检索时限为建库以来至2023年8月1日。共3名研究者进行文献筛选及质量评估,将满足质量标准的文献进行Meta分析。结果本研究共纳入13个前后对照试验,总样本量281例。Meta分析结果显示,治疗后颌骨矢状向及垂直向指标与治疗前相比差异无统计学意义(P>0.05);治疗后上颌第一磨牙远中移动量MD=-2.34,95%CI(-2.83,-1.85),压低移动量MD=-0.95,95%CI(-1.34,-0.56),远中倾斜量MD=-2.51,95%CI(-3.56,-1.46),与治疗前相比差异均有统计学意义(P<0.05);治疗后上颌切牙平均内收距离MD=-0.82,95%CI(-1.54,-0.09),唇倾度减小MD=-1.61,95%CI(-2.86,-0.36),与治疗前相比差异均有统计学意义(P<0.05)。结论隐形矫治器能够有效远中移动上颌磨牙并控制磨牙垂直向位置,磨牙远移的同时伴有一定的压低及远中倾斜移动,对高角型患者有利。上颌切牙的矢状向内收有利于患者侧貌的改善。展开更多
检索PubMed、Web of Science、中国知网等数据库中有关喉返神经损伤(RLNI)在甲状腺手术中的研究。关键词包括喉返神经修复、注射喉成形术、Ⅰ型甲状腺成形术、杓状软骨内收术、神经组织工程技术等。总结和比较目前RLNI的常见治疗方法。...检索PubMed、Web of Science、中国知网等数据库中有关喉返神经损伤(RLNI)在甲状腺手术中的研究。关键词包括喉返神经修复、注射喉成形术、Ⅰ型甲状腺成形术、杓状软骨内收术、神经组织工程技术等。总结和比较目前RLNI的常见治疗方法。结果显示,喉返神经直接缝合是目前修复的首选术式,颈袢-喉返神经吻合术最常用于临床,其他修复方式各有其优、缺点。大多数治疗方法可在一定程度上获得不同的效果,但仍存在需进一步克服的缺点。此外神经组织工程技术及中医康复治疗值得进一步探索关注。展开更多
A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentr...A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate （Li2CO3） to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li2CO3 and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li2CO3 to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.展开更多
Objective To investigate the application of BPDE-albumin adducts as monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons （PAHs） and to explore possible relationship between BPDE-al...Objective To investigate the application of BPDE-albumin adducts as monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons （PAHs） and to explore possible relationship between BPDE-albumin adducts and urinary 1-hydroxypyrene （1-OHP） levels in them. Methods Thirty-seven coke oven workers from a coke plant and 47 controls without the occupational exposure to PAHs were recruited in this study. The levels of plasma BPDE-albumin adducts and urinary 1-OHP were analyzed using high performance liquid chromatography. Results The median levels of BPDE-albumin adducts （42.10 fmol/mg albumin） and urinary 1-OHP （5.46 μmol/mol creatinine） were significantly higher in coke oven workers than in controls （14.16 fmol/mg albumin, 2.96μmol/mol creatinine, respectively; P〈0.01）. Multiple logistic regression analysis showed that coke oven workers were at higher risk of having BPDE-albumin adduct levels above 25.30 μmol/mg albumin （OR=1.79, P〈0.01） and urinary 1-OHP levels above 4.13 μmol/mol creatinine （OR=2.45, P〈0.05）. There was a positive correlation between the levels of BPDE-albumin adducts and urinary 1-OHP in all subjects （rs=0.349, P〈0.01）. Conclusion BPDE-albumin adduct is a useful biomarker for monitoring long-term exposure to PAHs, and plasma BPDE-albumin adducts level is significantly correlated to urinary 1-OHP levels in coke oven workers.展开更多
AIM The food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces colon and mammary gland tumors in rats and has been implicated in the etiology of human colorectal cancer. This study was co...AIM The food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces colon and mammary gland tumors in rats and has been implicated in the etiology of human colorectal cancer. This study was conducted to examine the potentially preventive effect of Chinese cabbage (Brassica chinensis), a brassica vegetable most commonly consumed in China, against this carcinogen-induced DNA adduct formation in rats and its possible mechanisms.METHODS Sprague-Dawley rats were maintained for 10 days on basal diet or diet containing 20% (w/ w) freeze-dried cabbage powder prior to administration of a single dose of PhIP (10 mg/ kg) by oral gavage. Rats were sacrificed at 20 h after PhIP treatment and PhIP-DNA adducts in the colon, heart, lung and liver were analyzed using 32P-postlabeling technique. Levels of hepatic cytochrome P450 (CYP) 1A1 and 1A2, as indicated by 7-ethoxyresorufin O-deethylase and 7-methlxyresorufin O-demethylase activity, and cytosolic glutathione S-transferases (GSTs) towards 1-chloro-2, 4-dinitrobenzene (CDNB) in the liver, lung and colon were measured.RESULTS Rats pre-treated with Chinese cabbage and given a single dose of PhIP had reduced levels of PhIP-DNA adducts in the colon, heart, lung and liver, with inhibition rates of 82.3%, 60.6%, 48.4% and 48.9%, respectively (P＜0.01). The enzyme assays revealed that Chinese cabbage induced both CYP1A1 and 1A2 activity, but the induction was preferential for CYP1A1 over 1A2 (81% vs 51%). GST activity towards CDNB in the liver and lung, but not colon, was also significantly increased by cabbage treatment.CONCLUSION The results indicate that Chinese cabbage has a preventive effect on PhIP-initiated carcinogenesis in rats and the mechanism is likely to involve the induction of detoxification enzymes.展开更多
A novel supramolecular adduct 3(C 42H 42N 28O 14) 2·H 2O (1) was synthesized by mixing 2- and cucurbit uril in solution of hydrochloric acid. The crystal structure was determined by single crys...A novel supramolecular adduct 3(C 42H 42N 28O 14) 2·H 2O (1) was synthesized by mixing 2- and cucurbit uril in solution of hydrochloric acid. The crystal structure was determined by single crystal X-ray diffraction analysis. The crystal belongs to orthorhombic system and space group F dd2 with cell dimensions: a=4.705 33 (5) nm, b=7.153 80 (6) nm, c= 1.894 61 (2) nm, Z=16, V=63.7744 (11) nm3, D c= 1.534 g/cm3, μ=3.007 mm -1, F(000)=29 120, R 1= 0.070 7, wR 2=0.169 2. In crystal, the cucurb uril molecules form two zig-zag chains.展开更多
Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes ma...Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes may experience an increased risk of genotoxicity. This study was designed to investigate whether the polymorphisms of two genes, the metabolic gene Glutathione S-transferase M1 （GSTM1） and DNA repair gene x-ray repair cross-complementing group 3 （XRCC3）, can affect the levels of AFB1-DNA adducts in Guangxi Population （n= 966） from an AFB1-exposure area. Methods： AFB1-DNA adducts were measured by ELISA, and GSTM1 and XRCC3 codon 241 genotypes were identified by PCR-RFLP. Results： The GSTM1-null genotype [adjusted odds ratio （OR） = 2.09; 95% confidence interval （CI） = 1.61-2.71] and XRCC3 genotypes with 241 Met alleles [i.e., XRCC3-TM and -MM, adjusted ORs （95% CI） were 1.43 （1.08-1.89） and 2.42 （1.13-5.22）, respectively] were significantly associated with higher levels of AFB1-DNA adducts. Compared with those individuals who did not express any putative risk genotypes as reference （OR = 1）, individuals featuring all of the putative risk genotypes did experience a significantly higher DNA-adduct levels （adjusted ORs were 2.87 for GSTM1-null and XRCC3-TM; 5.83 for GSTM1-null and XRCC3-MM）. Additionally, there was a positive joint effect between XRCC3 genotypes and long-term AFB1 exposure in the formation of AFB1-DNA adducts. Conclusion： These results suggest that individuals with susceptible genotypes GSTM1-null, XRCC3-TM, or XRCC3-MM may experience an increased risk of DNA damage elicited by AFB1 exposure.展开更多
A new Diels-Alder type adduct mongolicin G （1） and a new flavone 5＇-（1＂, 1＂-dimethylallyl）-5,7,2＇,4＇-tetrahydroxyflavone （2） were isolated from the stem and root bark of Morus mongolica. Their structures we...A new Diels-Alder type adduct mongolicin G （1） and a new flavone 5＇-（1＂, 1＂-dimethylallyl）-5,7,2＇,4＇-tetrahydroxyflavone （2） were isolated from the stem and root bark of Morus mongolica. Their structures were determined by spectroscopic analysis and chiroptical methods.展开更多
A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the pre...A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.展开更多
The B3LYP/6-31G^＊ level of theory was used to optimize trans-[Pt（NH3）（Am）G-L], where Am = quinoline or thiazole and L is chosen as the model for functional groups of peptide side chains, and for adenine and guani...The B3LYP/6-31G^＊ level of theory was used to optimize trans-[Pt（NH3）（Am）G-L], where Am = quinoline or thiazole and L is chosen as the model for functional groups of peptide side chains, and for adenine and guanine sites of DNA as the ultimate target of platinum anticancer drugs. Bond dissociating energy and stability energy of complexes are chosen to study detailedly thermodynamic character of possible difunctional adducts model. In order to investigate the influence of a polarizable environment on the energy of the Pt-L bond formation, we adopt a new bonding energy formula brought forward by Lippard and his coworkers： △H（Sol） = △H（SCF） ＋ △G（Solv）, which is quite appropriate to compare with what is found in experimental studies. Our calculated results demonstrate that N-containing ligands are more favored in view of thermodynamics both in gas phrase and in solution. However, it is worthly to be noted that addition of solvation free energies result in moderate correction of bonding energy in relative ordering, and the largest ones both present in imidazole ligand, not in guanine ligand. Finally, the nature of bond is analyzed in terms of partial charges distribution based on NBO population.展开更多
文摘DNA adduction with nicotine-derived nitrosamine, 4-(methylnitrosamino)-1-(3- pyridy1)-1 -butanone (NNK) in mice at doses equivalent to human exposure has been studied using 14C-label by accelerator mass spectrometry(AMS). A detection limit of DNA adducts of 1 adduct Per 1010 nucleotides has been achieved. This sensitivity of AMS measurement is 3 or more orders of magnitude improved than that of radioimmunoassay.Formation of DNA adducts is linearly dependent on dose down to an exposure of 100 ng Per kg of body weight .The ultimate cheeical form of carcinogen NNK binding to DNA is speculated.
文摘目的评价无托槽隐形矫治器远中移动成年患者上颌磨牙的临床疗效,以提高正畸医生对疗效的预估性。方法检索Web of Science、The Cochrane Library、Embase、Pubmed、万方数据库、知网数据库、维普数据库公开发表的隐形矫治器远移成年患者上颌磨牙疗效的研究。检索时限为建库以来至2023年8月1日。共3名研究者进行文献筛选及质量评估,将满足质量标准的文献进行Meta分析。结果本研究共纳入13个前后对照试验,总样本量281例。Meta分析结果显示,治疗后颌骨矢状向及垂直向指标与治疗前相比差异无统计学意义(P>0.05);治疗后上颌第一磨牙远中移动量MD=-2.34,95%CI(-2.83,-1.85),压低移动量MD=-0.95,95%CI(-1.34,-0.56),远中倾斜量MD=-2.51,95%CI(-3.56,-1.46),与治疗前相比差异均有统计学意义(P<0.05);治疗后上颌切牙平均内收距离MD=-0.82,95%CI(-1.54,-0.09),唇倾度减小MD=-1.61,95%CI(-2.86,-0.36),与治疗前相比差异均有统计学意义(P<0.05)。结论隐形矫治器能够有效远中移动上颌磨牙并控制磨牙垂直向位置,磨牙远移的同时伴有一定的压低及远中倾斜移动,对高角型患者有利。上颌切牙的矢状向内收有利于患者侧貌的改善。
文摘检索PubMed、Web of Science、中国知网等数据库中有关喉返神经损伤(RLNI)在甲状腺手术中的研究。关键词包括喉返神经修复、注射喉成形术、Ⅰ型甲状腺成形术、杓状软骨内收术、神经组织工程技术等。总结和比较目前RLNI的常见治疗方法。结果显示,喉返神经直接缝合是目前修复的首选术式,颈袢-喉返神经吻合术最常用于临床,其他修复方式各有其优、缺点。大多数治疗方法可在一定程度上获得不同的效果,但仍存在需进一步克服的缺点。此外神经组织工程技术及中医康复治疗值得进一步探索关注。
基金ACKNOWLEDGMENTS This work was supported by the Innovation Foundation of Graduate Students in University of Science and Technology of China （No.KD2008020）, and the Natural Science Foundation of Anhui Province （No.090416228）.
文摘A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate （Li2CO3） to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li2CO3 and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li2CO3 to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.
基金This study was supported by National Key Basic Research and Development Program of China (No.2002CB512905)National Natural Science Foundation of China (No.30371204).
文摘Objective To investigate the application of BPDE-albumin adducts as monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons （PAHs） and to explore possible relationship between BPDE-albumin adducts and urinary 1-hydroxypyrene （1-OHP） levels in them. Methods Thirty-seven coke oven workers from a coke plant and 47 controls without the occupational exposure to PAHs were recruited in this study. The levels of plasma BPDE-albumin adducts and urinary 1-OHP were analyzed using high performance liquid chromatography. Results The median levels of BPDE-albumin adducts （42.10 fmol/mg albumin） and urinary 1-OHP （5.46 μmol/mol creatinine） were significantly higher in coke oven workers than in controls （14.16 fmol/mg albumin, 2.96μmol/mol creatinine, respectively; P〈0.01）. Multiple logistic regression analysis showed that coke oven workers were at higher risk of having BPDE-albumin adduct levels above 25.30 μmol/mg albumin （OR=1.79, P〈0.01） and urinary 1-OHP levels above 4.13 μmol/mol creatinine （OR=2.45, P〈0.05）. There was a positive correlation between the levels of BPDE-albumin adducts and urinary 1-OHP in all subjects （rs=0.349, P〈0.01）. Conclusion BPDE-albumin adduct is a useful biomarker for monitoring long-term exposure to PAHs, and plasma BPDE-albumin adducts level is significantly correlated to urinary 1-OHP levels in coke oven workers.
基金Supported by the National Natural Science Foundation of China,No.39570627.
文摘AIM The food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces colon and mammary gland tumors in rats and has been implicated in the etiology of human colorectal cancer. This study was conducted to examine the potentially preventive effect of Chinese cabbage (Brassica chinensis), a brassica vegetable most commonly consumed in China, against this carcinogen-induced DNA adduct formation in rats and its possible mechanisms.METHODS Sprague-Dawley rats were maintained for 10 days on basal diet or diet containing 20% (w/ w) freeze-dried cabbage powder prior to administration of a single dose of PhIP (10 mg/ kg) by oral gavage. Rats were sacrificed at 20 h after PhIP treatment and PhIP-DNA adducts in the colon, heart, lung and liver were analyzed using 32P-postlabeling technique. Levels of hepatic cytochrome P450 (CYP) 1A1 and 1A2, as indicated by 7-ethoxyresorufin O-deethylase and 7-methlxyresorufin O-demethylase activity, and cytosolic glutathione S-transferases (GSTs) towards 1-chloro-2, 4-dinitrobenzene (CDNB) in the liver, lung and colon were measured.RESULTS Rats pre-treated with Chinese cabbage and given a single dose of PhIP had reduced levels of PhIP-DNA adducts in the colon, heart, lung and liver, with inhibition rates of 82.3%, 60.6%, 48.4% and 48.9%, respectively (P＜0.01). The enzyme assays revealed that Chinese cabbage induced both CYP1A1 and 1A2 activity, but the induction was preferential for CYP1A1 over 1A2 (81% vs 51%). GST activity towards CDNB in the liver and lung, but not colon, was also significantly increased by cabbage treatment.CONCLUSION The results indicate that Chinese cabbage has a preventive effect on PhIP-initiated carcinogenesis in rats and the mechanism is likely to involve the induction of detoxification enzymes.
文摘A novel supramolecular adduct 3(C 42H 42N 28O 14) 2·H 2O (1) was synthesized by mixing 2- and cucurbit uril in solution of hydrochloric acid. The crystal structure was determined by single crystal X-ray diffraction analysis. The crystal belongs to orthorhombic system and space group F dd2 with cell dimensions: a=4.705 33 (5) nm, b=7.153 80 (6) nm, c= 1.894 61 (2) nm, Z=16, V=63.7744 (11) nm3, D c= 1.534 g/cm3, μ=3.007 mm -1, F(000)=29 120, R 1= 0.070 7, wR 2=0.169 2. In crystal, the cucurb uril molecules form two zig-zag chains.
基金supported by the National Natural Science Foundation of China (No.39860032)the Youth Science Foundation of Guangxi (No.0833097)
文摘Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes may experience an increased risk of genotoxicity. This study was designed to investigate whether the polymorphisms of two genes, the metabolic gene Glutathione S-transferase M1 （GSTM1） and DNA repair gene x-ray repair cross-complementing group 3 （XRCC3）, can affect the levels of AFB1-DNA adducts in Guangxi Population （n= 966） from an AFB1-exposure area. Methods： AFB1-DNA adducts were measured by ELISA, and GSTM1 and XRCC3 codon 241 genotypes were identified by PCR-RFLP. Results： The GSTM1-null genotype [adjusted odds ratio （OR） = 2.09; 95% confidence interval （CI） = 1.61-2.71] and XRCC3 genotypes with 241 Met alleles [i.e., XRCC3-TM and -MM, adjusted ORs （95% CI） were 1.43 （1.08-1.89） and 2.42 （1.13-5.22）, respectively] were significantly associated with higher levels of AFB1-DNA adducts. Compared with those individuals who did not express any putative risk genotypes as reference （OR = 1）, individuals featuring all of the putative risk genotypes did experience a significantly higher DNA-adduct levels （adjusted ORs were 2.87 for GSTM1-null and XRCC3-TM; 5.83 for GSTM1-null and XRCC3-MM）. Additionally, there was a positive joint effect between XRCC3 genotypes and long-term AFB1 exposure in the formation of AFB1-DNA adducts. Conclusion： These results suggest that individuals with susceptible genotypes GSTM1-null, XRCC3-TM, or XRCC3-MM may experience an increased risk of DNA damage elicited by AFB1 exposure.
基金the National Natural Science Foundation of China(NO.20432030)for financial support.
文摘A new Diels-Alder type adduct mongolicin G （1） and a new flavone 5＇-（1＂, 1＂-dimethylallyl）-5,7,2＇,4＇-tetrahydroxyflavone （2） were isolated from the stem and root bark of Morus mongolica. Their structures were determined by spectroscopic analysis and chiroptical methods.
基金the National Natural Science Foundation of China （No. 20072033）Specialized Research Fund for the Doctoral Program of Higher Education of China.
文摘A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.
基金This work was supported by the Science Foundation of Jinan University (639)
文摘The B3LYP/6-31G^＊ level of theory was used to optimize trans-[Pt（NH3）（Am）G-L], where Am = quinoline or thiazole and L is chosen as the model for functional groups of peptide side chains, and for adenine and guanine sites of DNA as the ultimate target of platinum anticancer drugs. Bond dissociating energy and stability energy of complexes are chosen to study detailedly thermodynamic character of possible difunctional adducts model. In order to investigate the influence of a polarizable environment on the energy of the Pt-L bond formation, we adopt a new bonding energy formula brought forward by Lippard and his coworkers： △H（Sol） = △H（SCF） ＋ △G（Solv）, which is quite appropriate to compare with what is found in experimental studies. Our calculated results demonstrate that N-containing ligands are more favored in view of thermodynamics both in gas phrase and in solution. However, it is worthly to be noted that addition of solvation free energies result in moderate correction of bonding energy in relative ordering, and the largest ones both present in imidazole ligand, not in guanine ligand. Finally, the nature of bond is analyzed in terms of partial charges distribution based on NBO population.
