Objective Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells a...Objective Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown. Methods We assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay). Results Exposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 (mol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells. Conclusion These data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.展开更多
To evaluate the genotoxic and nongenotoxic effects of short-term exposure to glycidyl mathacrylate (GMA) on human lung fibroblast cells (2BS cells) in vitro. Methods DNA strand breakage was determined by single cell g...To evaluate the genotoxic and nongenotoxic effects of short-term exposure to glycidyl mathacrylate (GMA) on human lung fibroblast cells (2BS cells) in vitro. Methods DNA strand breakage was determined by single cell gel electrophoresis, and DNA ladder formation assay and flow cytometric analysis were carried out to detect apoptic responses of cells to GMA exposure.The HPRT gene mutation assay was used to evaluate the mutagenicity, and the effect of GMA on gap junctional intercellular communication (GJIC) in the exposed cells was examined with the scrape loading/dye transfer technique. The ability of GMA to transform 2BS cells was also tested by an in vitro cell transformation assay. Results Exposure to GMA resulted in a dose-dependent increase in DNA strand breaks but not apoptic responses. GMA was also shown to significantly induce HPRT gene mutations and morphological transformation in 2BS cells in vitro. In contrast, GMA produced a concentration-dependent inhibition of GJIC. Conclusions GMA elicits both genotoxic and nongenotoxic effects on 2BS cells in vitro. The induction of DNA damage and gene mutations and inhibition of GJIC by GMA may casually contribute to GMA-induced cell transformation.展开更多
A HPLC Assay was developed to indentify and measure the metabolite of acrylamide,mercapturic acid,N-Acetyl-s-(propionamide)-cyteine(APC)in urine O-phthalaldehyde (OPA)was utilized as a precolumm derivatizing agent i...A HPLC Assay was developed to indentify and measure the metabolite of acrylamide,mercapturic acid,N-Acetyl-s-(propionamide)-cyteine(APC)in urine O-phthalaldehyde (OPA)was utilized as a precolumm derivatizing agent in the assay.This derivative was isolated with a good selectivity by high performance liquid chromatography(HPLC)employing reversed phase ODS columns.The quantiation of the mercapturic acid derivative was reproducible and with a detection limit of 1 pmol.The average coefficient of variation for the runs carried out on the same day was approximately 4.6% at the range of 80-160μmol·l^-1 of APC,and the mean analytical recovery from urine samples was 94%.The metabolite of urine of workers exposed to acrylamide was identified as N-acetyl-s-(propionamide)-cysteine by HPLC chromatography and fluorescence scan and HPLC-Mass spectra.All results were identical with the authentic synthesized compound.展开更多
The effects of acrylamide on calmoduline(CaM),cAMP,cGMP,Ca^2+,Mg^2+-ATPase and ^45Ca^2+ uptake in nervous system were detrmined in Wistar rats(ip,10or 50mg·kg^-1 for 12d),The results indicate that acrylamide caus...The effects of acrylamide on calmoduline(CaM),cAMP,cGMP,Ca^2+,Mg^2+-ATPase and ^45Ca^2+ uptake in nervous system were detrmined in Wistar rats(ip,10or 50mg·kg^-1 for 12d),The results indicate that acrylamide caused an alteration in calcium homeostasis in rat brain by decreasing the Ca^2+ -sequestering capacity of microsomes,and this may occur due to an efflux of calcium secondary to a microsomal structure damage.The changes of CaM in nervous system coupled with potential alteration in the intracellular Ca^2+ concentration could affect many CaM-dependent enzymes(i.e.Ca^2+,Mg^2+-ATPase)and cyclic AMP system,and CaM or cAMP is known to be“toxicological second messenger”that could initiate neurotoxicity,though more work is needed to elucidate the details of the mechanism.展开更多
In vivo cytotoxicity including cellular metabolic activity, lysozyme content and total protein content in rat bronchoalveolar lavage, capacity of interleukin-1 released from rat pulmonary cells and fibrogenic effects ...In vivo cytotoxicity including cellular metabolic activity, lysozyme content and total protein content in rat bronchoalveolar lavage, capacity of interleukin-1 released from rat pulmonary cells and fibrogenic effects evaluated from rat lung dry weight, collagen content of the whole lung and pathological grading induced by mineral dust were assayed. The results showed that: (1) The relationship among in vivo cytotoxicity, interleukin-1 release,fibrogenic effects on the lung induced by mineral dusts correlated well with the free SiO2content in mineral dusts in most (but not all) cases; (2) The biological harmful effects of mixed dusts were not simply the additive effect of single dust. In the group of WO3-SiO2mixture, the fibrogenicity was mainly due to SiO2, tungsten trioxide (WO3) showed neither fibrogenic effect, nor significant potentiality to enhance SiO2 fibrogenicity, while in the group of SnO2-SiO2, SnO2 was suppressive to the effect of SiO2, although the contents of SiO2 in the two mixed dusts were展开更多
The effects of IL-2,IL-2,and IL-4 activities on occurrence of allergic asthma induced by spores of mushroom have been studied by measuring the IL-2,IL-3,and IL-4 activities in culture supernatants of spleen lymphocyte...The effects of IL-2,IL-2,and IL-4 activities on occurrence of allergic asthma induced by spores of mushroom have been studied by measuring the IL-2,IL-3,and IL-4 activities in culture supernatants of spleen lymphocytes from guinea pige being stimulated with Con A.The ,IL-4 activity(14.9±.48u)in the culture supernatant was higher than control group (6.7±1.5u).The IL-2 activities were all similar to that of the control group.The IL-4 synthesis was similarly raised as the IL-4 activity.These results indicated that there is a relationship etween the occurrence of allergic asthma and the increase of IL-4.展开更多
The evaluation of luminol-dependent chemiluminescence(CL)for determination of free radicals generated during the oxidative reactions of microsomal enzymes in microsomes and reconstituted systms has been studied.The r...The evaluation of luminol-dependent chemiluminescence(CL)for determination of free radicals generated during the oxidative reactions of microsomal enzymes in microsomes and reconstituted systms has been studied.The results indicated that the CL not only depended on NADPH induction but also on intact cytochrome P-450 enzymes.The light emission signal was strongly scavended by SOD with inhibition rate of 93%.A concentration of 24μmol·L^-1 cadmium acetate and 2.5μmol·L^-1 mercuric chloride also inhibited the signal significantly as compared with the control.The study of CL in detecting free radicals formed by biotransformation of 44 xenobiotics suggested that some of the compounds known as free radicals producing agents by bioactivation increased the light emission in cytochroe P-450 enzyme system,such as carbon tetrachloride,chloroform,tetrachloroethylene etc.,the others forming toxic metabolites by biotransformation induced the CL in some cases,such as carbon disulfide,benzene,methyldursban,methylparathion etc.or decreased the light emission,such as parathion,aniline and polychlorinated byphenyls tc.,and still others whose toxic effects have no relationship with their biotransformation had no influence or an inhibitory effect on the CL,such as aminopyrine,TOCP,and acrylamide.CL in the cytochrome P-450 enzyme system remained unchanged during the biotransformation of carcinogens such as diethylitrosamine,dipropylitrosamine and benzo(a)pyrene as compared with the control.However,3-methylcholanthrene and dimethylnitrosamine had an enhancing effect on the CL,while 2acetylaminofluorene and 2-aminoanthracene showed an inhibition to the signals.展开更多
A gas chromatographic method for the determination of deltamethrin and fenvalerate in human urine is described. Both deltamethrin and fenvalerate have been analysed by gas chromatography with a electron capture detect...A gas chromatographic method for the determination of deltamethrin and fenvalerate in human urine is described. Both deltamethrin and fenvalerate have been analysed by gas chromatography with a electron capture detector. The least detectable concentration of both pyrethroids in urine is 0.2 g per litre. The precision and accuracy of the method were within acceptable limits. The method has been used to determine the pyrethroids in urine samples obtained from packers, spraymen and acute pyrethroids poisoning展开更多
In order to provide scientific information on the prevention and treatment of silicosis,studies about changes of silicotic collagen in lungs were carried out. In this paper, we present experiments about the structural...In order to provide scientific information on the prevention and treatment of silicosis,studies about changes of silicotic collagen in lungs were carried out. In this paper, we present experiments about the structural changes of collagen in silicotic lungs of rats and patients. These included electron microscopy, circular dichroism and infrared spectroscopy studies of collagen fibers. The results indicated that fibers of silicotic collagen were shorter in length, smaller in diameter and decreased in α-helix content. The -Si-O-R- group and -OH group were found increased and -C-C- backbone shortened. The increase of -Si-O-R-group indicated that silica formed linking bridges between collagens which may be the cause of progressive enlargement of展开更多
In order to chitracterizc the speclrum of mutallon indueed by glyeidyl methacrylule(GMA ), the plasmid pBR322 was modificed with this mutagen in vitro , transttclcd intoapproprate Escherichia colii host HB101. The mut...In order to chitracterizc the speclrum of mutallon indueed by glyeidyl methacrylule(GMA ), the plasmid pBR322 was modificed with this mutagen in vitro , transttclcd intoapproprate Escherichia colii host HB101. The mutants were then sereened and defined by DNA sequencing . Sequence analysis reveals that G MA induces two classes of mulations deletion of the mono-. di’ or fetra-base or the insertion of mono’ or di-base. Both typesof mutations, with about 10 % frequency. occur predominantly at C-G runs and at5’-CNCCN-3’ sequence ,which are hotspots for GMA damage and may cause frameshift mutation.展开更多
基金This work was supported by grants from the National Natural Science Foundation of China (NNSFC) and the National Key Basic Research and Development Program to WT (2002 CB512905) by a collaborative exchange grant between the NNSFC and the CIHR of Canad
文摘Objective Benzo[a]pyrene (B[a]P), a ubiquitous environmental pollutant, is a potent procarcinogen and mutagen that can elicit tumors, leading to malignancy. Heat shock proteins (Hsp) have been shown to protect cells against damages caused by various stresses including exposure to numerous chemicals. Whether Hsps, or more specifically Hsp70, are involved in repair of B[a]P-induced DNA damage is currently unknown. Methods We assessed the potential role of the inducible form of Hsp70 in B[a]P-induced DNA damage of human embryonic lung (HEL) cells using immunoblot and the comet assay (i.e., the single cell gel electrophoresis assay). Results Exposure to B[a]P induced a dose-dependent decrease in the level of Hsp70, but a dose-dependent increase in DNA damage both in untreated (control) HEL cells and in cells preconditioned by a heat treatment. Heat preconditioning prior to B[a]P exposure potentiated the effect of B[a]P at a low dose (10 (mol/L), but appeared to be protective at higher doses. There was a negative correlation between Hsp70 level and DNA damage in the non-preheated as well as in the preconditioned cells. Conclusion These data suggest that exposure of HEL cells to B[a]P may induce a dose-dependent reduction in the levels of the inducible Hsp70. The detailed mechanisms for the reduction of Hsp70 levels by B[a]P and the role of Hsp70 in DNA damage under different concentrations of B[a]P remains to be determined.
基金This work was supported by a grant from the National Natural Science Foundation of China (grant no. 39840017).
文摘To evaluate the genotoxic and nongenotoxic effects of short-term exposure to glycidyl mathacrylate (GMA) on human lung fibroblast cells (2BS cells) in vitro. Methods DNA strand breakage was determined by single cell gel electrophoresis, and DNA ladder formation assay and flow cytometric analysis were carried out to detect apoptic responses of cells to GMA exposure.The HPRT gene mutation assay was used to evaluate the mutagenicity, and the effect of GMA on gap junctional intercellular communication (GJIC) in the exposed cells was examined with the scrape loading/dye transfer technique. The ability of GMA to transform 2BS cells was also tested by an in vitro cell transformation assay. Results Exposure to GMA resulted in a dose-dependent increase in DNA strand breaks but not apoptic responses. GMA was also shown to significantly induce HPRT gene mutations and morphological transformation in 2BS cells in vitro. In contrast, GMA produced a concentration-dependent inhibition of GJIC. Conclusions GMA elicits both genotoxic and nongenotoxic effects on 2BS cells in vitro. The induction of DNA damage and gene mutations and inhibition of GJIC by GMA may casually contribute to GMA-induced cell transformation.
基金Project supported by the National Natural Science Foundation of China.
文摘A HPLC Assay was developed to indentify and measure the metabolite of acrylamide,mercapturic acid,N-Acetyl-s-(propionamide)-cyteine(APC)in urine O-phthalaldehyde (OPA)was utilized as a precolumm derivatizing agent in the assay.This derivative was isolated with a good selectivity by high performance liquid chromatography(HPLC)employing reversed phase ODS columns.The quantiation of the mercapturic acid derivative was reproducible and with a detection limit of 1 pmol.The average coefficient of variation for the runs carried out on the same day was approximately 4.6% at the range of 80-160μmol·l^-1 of APC,and the mean analytical recovery from urine samples was 94%.The metabolite of urine of workers exposed to acrylamide was identified as N-acetyl-s-(propionamide)-cysteine by HPLC chromatography and fluorescence scan and HPLC-Mass spectra.All results were identical with the authentic synthesized compound.
基金This work was supported by the Key Projects of the 7th Five-Year Plan from the State Commission of Science and Technology (No.75-62-03-30).
文摘The effects of acrylamide on calmoduline(CaM),cAMP,cGMP,Ca^2+,Mg^2+-ATPase and ^45Ca^2+ uptake in nervous system were detrmined in Wistar rats(ip,10or 50mg·kg^-1 for 12d),The results indicate that acrylamide caused an alteration in calcium homeostasis in rat brain by decreasing the Ca^2+ -sequestering capacity of microsomes,and this may occur due to an efflux of calcium secondary to a microsomal structure damage.The changes of CaM in nervous system coupled with potential alteration in the intracellular Ca^2+ concentration could affect many CaM-dependent enzymes(i.e.Ca^2+,Mg^2+-ATPase)and cyclic AMP system,and CaM or cAMP is known to be“toxicological second messenger”that could initiate neurotoxicity,though more work is needed to elucidate the details of the mechanism.
文摘In vivo cytotoxicity including cellular metabolic activity, lysozyme content and total protein content in rat bronchoalveolar lavage, capacity of interleukin-1 released from rat pulmonary cells and fibrogenic effects evaluated from rat lung dry weight, collagen content of the whole lung and pathological grading induced by mineral dust were assayed. The results showed that: (1) The relationship among in vivo cytotoxicity, interleukin-1 release,fibrogenic effects on the lung induced by mineral dusts correlated well with the free SiO2content in mineral dusts in most (but not all) cases; (2) The biological harmful effects of mixed dusts were not simply the additive effect of single dust. In the group of WO3-SiO2mixture, the fibrogenicity was mainly due to SiO2, tungsten trioxide (WO3) showed neither fibrogenic effect, nor significant potentiality to enhance SiO2 fibrogenicity, while in the group of SnO2-SiO2, SnO2 was suppressive to the effect of SiO2, although the contents of SiO2 in the two mixed dusts were
文摘The effects of IL-2,IL-2,and IL-4 activities on occurrence of allergic asthma induced by spores of mushroom have been studied by measuring the IL-2,IL-3,and IL-4 activities in culture supernatants of spleen lymphocytes from guinea pige being stimulated with Con A.The ,IL-4 activity(14.9±.48u)in the culture supernatant was higher than control group (6.7±1.5u).The IL-2 activities were all similar to that of the control group.The IL-4 synthesis was similarly raised as the IL-4 activity.These results indicated that there is a relationship etween the occurrence of allergic asthma and the increase of IL-4.
文摘The evaluation of luminol-dependent chemiluminescence(CL)for determination of free radicals generated during the oxidative reactions of microsomal enzymes in microsomes and reconstituted systms has been studied.The results indicated that the CL not only depended on NADPH induction but also on intact cytochrome P-450 enzymes.The light emission signal was strongly scavended by SOD with inhibition rate of 93%.A concentration of 24μmol·L^-1 cadmium acetate and 2.5μmol·L^-1 mercuric chloride also inhibited the signal significantly as compared with the control.The study of CL in detecting free radicals formed by biotransformation of 44 xenobiotics suggested that some of the compounds known as free radicals producing agents by bioactivation increased the light emission in cytochroe P-450 enzyme system,such as carbon tetrachloride,chloroform,tetrachloroethylene etc.,the others forming toxic metabolites by biotransformation induced the CL in some cases,such as carbon disulfide,benzene,methyldursban,methylparathion etc.or decreased the light emission,such as parathion,aniline and polychlorinated byphenyls tc.,and still others whose toxic effects have no relationship with their biotransformation had no influence or an inhibitory effect on the CL,such as aminopyrine,TOCP,and acrylamide.CL in the cytochrome P-450 enzyme system remained unchanged during the biotransformation of carcinogens such as diethylitrosamine,dipropylitrosamine and benzo(a)pyrene as compared with the control.However,3-methylcholanthrene and dimethylnitrosamine had an enhancing effect on the CL,while 2acetylaminofluorene and 2-aminoanthracene showed an inhibition to the signals.
文摘A gas chromatographic method for the determination of deltamethrin and fenvalerate in human urine is described. Both deltamethrin and fenvalerate have been analysed by gas chromatography with a electron capture detector. The least detectable concentration of both pyrethroids in urine is 0.2 g per litre. The precision and accuracy of the method were within acceptable limits. The method has been used to determine the pyrethroids in urine samples obtained from packers, spraymen and acute pyrethroids poisoning
文摘In order to provide scientific information on the prevention and treatment of silicosis,studies about changes of silicotic collagen in lungs were carried out. In this paper, we present experiments about the structural changes of collagen in silicotic lungs of rats and patients. These included electron microscopy, circular dichroism and infrared spectroscopy studies of collagen fibers. The results indicated that fibers of silicotic collagen were shorter in length, smaller in diameter and decreased in α-helix content. The -Si-O-R- group and -OH group were found increased and -C-C- backbone shortened. The increase of -Si-O-R-group indicated that silica formed linking bridges between collagens which may be the cause of progressive enlargement of
文摘In order to chitracterizc the speclrum of mutallon indueed by glyeidyl methacrylule(GMA ), the plasmid pBR322 was modificed with this mutagen in vitro , transttclcd intoapproprate Escherichia colii host HB101. The mutants were then sereened and defined by DNA sequencing . Sequence analysis reveals that G MA induces two classes of mulations deletion of the mono-. di’ or fetra-base or the insertion of mono’ or di-base. Both typesof mutations, with about 10 % frequency. occur predominantly at C-G runs and at5’-CNCCN-3’ sequence ,which are hotspots for GMA damage and may cause frameshift mutation.
