The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with ...The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with the CMOS circuit,but also acts on the protection circuit.This paper establishes a model of on-chip CMOS electrostatic discharge protection circuit and selects square pulse as the FREMP signals.Based on multiple physical parameter models,it depicts the distribution of the lattice temperature,current density,and electric field intensity inside the device.At the same time,this paper explores the changes of the internal devices in the circuit under the injection of fast rising time electromagnetic pulse and describes the relationship between the damage amplitude threshold and the pulse width.The results show that the ESD protection circuit has potential damage risk,and the injection of FREMP leads to irreversible heat loss inside the circuit.In addition,pulse signals with different attributes will change the damage threshold of the circuit.These results provide an important reference for further evaluation of the influence of electromagnetic environment on the chip,which is helpful to carry out the reliability enhancement research of ESD protection circuit.展开更多
Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a val...Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a validated radioprotectant extensively applied in radiation and chemotherapy medicine,but the short half-life limits its bioavailability and clinical applications,remaining as a great challenge to be addressed.DNAassembled nanostructures especially the tetrahedral framework nucleic acids(tFNAs)are promising nanocarriers with preeminent biosafety,low biotoxicity,and high transport efficiency.The tFNAs also have a relative long-term maintenance for structural stability and excellent endocytosis capacity.We therefore synthesized a tFNA-based delivery system of AMF for multi-organ radioprotection(tFNAs@AMF,also termed nanosuit).By establishing the mice models of accidental total body irradiation(TBI)and radiotherapy model of Lewis lung cancer,we demonstrated that the nanosuit could shield normal cells from IR-induced DNA damage by regulating the molecular biomarkers of anti-apoptosis and anti-oxidative stress.In the accidental total body irradiation(TBI)mice model,the nanosuit pretreated mice exhibited satisfactory alteration of superoxide dismutase(SOD)activities and malondialdehyde(MDA)contents,and functional recovery of hematopoietic system,reducing IRinduced pathological damages of multi-organ and safeguarding mice from lethal radiation.More importantly,the nanosuit showed a selective radioprotection of the normal organs without interferences of tumor control in the radiotherapy model of Lewis lung cancer.Based on a conveniently available DNA tetrahedron-based nanocarrier,this work presents a high-efficiency delivery system of AMF with the prolonged half-life and enhanced radioprotection for multi-organs.Such nanosuit pioneers a promising strategy with great clinical translation potential for radioactivity protection.展开更多
Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurri...Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC<sub>50</sub> for lycopene was determined at 112 μg/mL which was almost partial to IC<sub>50</sub> of standard antioxidant L-ascorbic acid. The D<sub>10</sub> value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC<sub>50</sub> concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals.展开更多
The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their...The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their DNA is damaged.The approach applied in this study is to test with COMET assay the damage of EM DNA in wastewater with different concentrations of heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,Zn2+,as well as the effects of EM treated with As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,and Zn2+ on COD degradin...展开更多
The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol.L-1) resulted in 60% inhibition of binding of 3H-benzo (...The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol.L-1) resulted in 60% inhibition of binding of 3H-benzo (a) pyrene to nuclear DNA. Unscheduled DNA synthesis (UDS) induced by aflatoxin BI (10^(-7) mol.L-1) in freshly isolated rat hepatocytes was also inhibited by DDB (10^(-6)-10^(-3)mol.L-1). Oral administration of DDB at 200 mg.kg-1 once daily for 3 d induced a significant increase of liver cytosol glutathione-S-transferase and microsomal UDPG-transferase activity in mice. These results indicate that DDB is able to directly or indirectly antagonize certain carcinogen-induced DNA damages.展开更多
To explore the anticancer mechanism and DNA damages of hydroxyapatite ultrofine powder (HAUFP) on lymphocytes of rats, DNA damages in W 256 sarcoma cells and lymphocytes of rats were measured by single cell gel elec...To explore the anticancer mechanism and DNA damages of hydroxyapatite ultrofine powder (HAUFP) on lymphocytes of rats, DNA damages in W 256 sarcoma cells and lymphocytes of rats were measured by single cell gel electrophoresis (SCGE). The results showed that HAUFP damaged DNA of W 256 sarcoma cells obviously but only cause slight damage of DNA of lymphocytes in rats. It is suggested that HAUFP selectively damaged DNA of tumor cells with only mild damage of lymphocyte DNA. HAUFP has powerful anticancer effect and little genetic toxicity.展开更多
The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently p...The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently protected the hepatocytes against carbon tetrachloride (CC14 10 mrnol.L-1) and D-galactosamine (1 mmol.L-1) induced damages. Membranal lipid peroxidation (malondialdehyde, MDA formation) and glutamic pyruvic transaminase (GPT) release from the hepatocytes were markedly decreased. The damage of the cell surfaces of the hepatocytes were also reduced as seen under a scanning electron microscope (SEM). Pretreatment with DDB (300 mg-kg-1) orally ameliorated the reduction of liver glycogen and blood glucose caused by ip injection of D-galactosamine (800 mg-kg-1) in mice. When normal rats were given DDB 300 mg-kg-1 once daily for 10 d, the free ribosomal protein and RNA in the liver increased significantly. These results indicate that DDB is of beneficial effects on both damaged and normal hepatocytes.展开更多
Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also pro...Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also protect rapid DNA damage and decrease the unscheduled DNA synthesis induced by benzo(α)pyrene. The results demonstrate that GA has a potential cancer chemopreventive activity.展开更多
The present study was performed to determine the influence of lipid peroxidation and perturbance of Ca2+ homeostasis on liver damage induced by 2-chloro-1, 3-butadiene (CBD) and the protective effects of vitamin E in ...The present study was performed to determine the influence of lipid peroxidation and perturbance of Ca2+ homeostasis on liver damage induced by 2-chloro-1, 3-butadiene (CBD) and the protective effects of vitamin E in Wistar rats. Animals were given intraperitoneally different doses (8,40 or 200 mg·kg-1 daily) of CBD for 21 days, and the following dose-dependent events were observed: liver damage, significant increase in liver lipid peroxides, and decreases in activities of erythrocytic glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). The pretreatment of rats with vitamin E (po 150 mg·kg-1) before administering CBD (iP 60 mg·kg-1 ) daily for 21 days prevented the following CBD-induced changes, the increase in serum cholylglycine (CG), hepatic LP, hepatic mitochondrion LP, hepatic oxidized glutathione (GSSG) (while the significant increase of reduced glutathione (GSH) was not affected) and the decrease in activities of erythrocytic SOD and hepatic mitochondrial calcium sequestration. These results suggest that lipid peroxidation and perturbance of Ca2+ homeostasis appear to contribute to the hepatotoxicity of CBD, and vitamin E might prevent the liver damage induced by CBD. The decrease in activities of GSH-Px and SOD in erythrocytes might be used as biomarkers for adverse effects of CBD on defense system against lipid peroxidation.展开更多
To treat many types of cancer, ionizing radiation （IR） is primarily used as external-beam radiotherapy, brachytherapy, and targeted radionuclide therapy. Exposure of tumor cells to JR can induce DNA damage as well a...To treat many types of cancer, ionizing radiation （IR） is primarily used as external-beam radiotherapy, brachytherapy, and targeted radionuclide therapy. Exposure of tumor cells to JR can induce DNA damage as well as generation of reactive oxygen species （ROS） and reactive nitrogen species （RNS） which can cause non-DNA lesions or extracellular damage like lipid perioxidation. The initial radiation-induced cell responses to DNA damage and ROS like the proteolytic processing, as well as synthesis and releasing ligands （such as growth factors, cytokines, and hormone） can cause the delayed secondary responses in irradiated and unirradiated bystander cells through paracrine and autocrine pathways.展开更多
Alzheimer’s disease（AD）is the most common type of dementia in elderly population.With a growing aging population not only in the United States but also in the worldwide,AD constitutes an emergent public health prob...Alzheimer’s disease（AD）is the most common type of dementia in elderly population.With a growing aging population not only in the United States but also in the worldwide,AD constitutes an emergent public health problem.展开更多
In order to observe it blockers of sodium channel obsesses the neuroprotective effect on hippocampal CA 1 pyramidal cell under the condition of transient brain ischemia, the present experiment used 24 male Wistar rat...In order to observe it blockers of sodium channel obsesses the neuroprotective effect on hippocampal CA 1 pyramidal cell under the condition of transient brain ischemia, the present experiment used 24 male Wistar rats aged 9 months and divided them into four groups. Lidocaine and/or furosemide were injected introcerebroventicularlly (I.C.V). Stained with H E and accounted the CA 1 pyramidal cell numbers by computer in each group suggested following findings: Although 5 μl of 2% lidocaine was injected I.C.V, the results indicated lidocaine didn't have any blockade to pyramidal cell injuries in hippocampal CA 1 area (P<0 05). In the group medicated with 2 5μl of both 2% lidocaine and 2% furosemide, the results showed that the combined approach had a blockade to injuries of pyramidal cells compared with control group (P<0 01). The present experiment indicates that the combined blockade of lidocaine and furosemide injected I.C.V. to Na + channel can prevent the injuries from hippocampal neurons owing to ischemia.展开更多
In this study, two common pollutants (benzo[a]pyrene and methamidophos) in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy ( Acanthopagr...In this study, two common pollutants (benzo[a]pyrene and methamidophos) in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy ( Acanthopagrus schlegeli). The fish was exposed to 2 μg/L of benzo[a]pyrene (BaP) and methamidophos, and their mixture. The assay was performed on whole blood at 2 h, 5 h, 24 h and 96 h exposure intervals. A signifi- cant increase in DNA damage was observed in each treatment with the pollutants. Additive effect of BaP and methamidophos was also found in the experiment. However, the decrease ratios of DNA damage for 5 h and 96 h exposure interals compared with 2 h and 24 h exposure ones, respectively, were noticed. This phenomenon may be explained by the function of repairing process via enzyme cytochrome P450 in the animal. Evidence of the genotoxicity of organophosphorus pesticides (OPs) and polynuclear aromatic hydrocarbons (PAHs) on marine fish are discussed in this paper.展开更多
Background: There are many programs which focus on late-stage chronic kidney disease (CKD), and it is considered that further evidence needs to be generated regarding the effectiveness of the programs used before rena...Background: There are many programs which focus on late-stage chronic kidney disease (CKD), and it is considered that further evidence needs to be generated regarding the effectiveness of the programs used before renal replacement therapy. Study Design: A cohort study. Settings & Participants: Patients over 15 years of age who had been diagnosed with CKD according to the KDOQI (Kidney Disease Outcomes Quality Initiative) guidelines and who had undergone conventional treatment (CT) or a renal protection program (RPP). These were patients of two Colombian health insurance companies. Predictors: Age, sex, marital status, comorbidities, CKD stage, and clinical indicators. Outcomes: First CKD progression, and need for renal replacement therapy (RRT). Measures: Clinical marker. Results: The RPP is structurally and functionally different from the CT. It offers the interdisciplinary management of patients, a greater number of medical appointments, and patients start to receive treatment at younger ages and at earlier stages of their condition. The clinical markers of the patients following the RPP are within adequate ranges, and their renal function is less impaired, despite the differences in basal conditions. Upon finishing the study, we found that patients who received CT had a higher risk of receiving nephrotoxic drugs and not receiving nephroprotective drugs. The explanatory variables for the first progression were age, stage, history of dyslipidemia, and hemoglobin, potassium, and albumin levels. These variables, together with glycemia levels were also valid for RRT, except for history of dyslipidemia, as it was not significant. Upon adjusting for the explanatory variables, it was found that belonging to the RPP and attending more appointments had a protective effect in the process of controlling renal damage. Limitations: A possible selection bias. Conclusions: Belonging to a structured renal protection program is an effective way to keeping the clinical markers associated with renal impairment within normal ranges.展开更多
The degree and characteristics of physical degradation of macro-DNA molecules by common laboratory manipulations are reported. With linearized lambda-phage viral DNA as the model DNA, fragmentation of macro-DNA by var...The degree and characteristics of physical degradation of macro-DNA molecules by common laboratory manipulations are reported. With linearized lambda-phage viral DNA as the model DNA, fragmentation of macro-DNA by various indispensable laboratory manipulations were investigated using a high sensitivity flow cytometric setup. Investigated manipulations included pipetting, vortexing, rocking, freeze-thawing, ultrasonication and ultrafiltration. “Exhaustive counting” of the intact lambda DNA molecules following such manipulations enabled a quantitative assessment of the resulting fragmentation, which also revealed the type of degradation reflected in the fragmentation patterns. The use of high sensitivity flow cytometry was especially suited to investigate the degradation of dilute DNA solutions that may not be suitable for analysis using traditional methods. Notable findings of this study included: the boarderline-size of DNA chains in terms of susceptibility to shear stresses by such manipulations;discernable instability of nicked DNAs;shattering-fragmentation of DNAs by freeze-thawing or ultrasonication;effectiveness of some protection media;marked “self-protection effect” of concentrated DNA solutions. These findings support and refine our traditional knowledge on how to maintain the physical integrity of macro-DNA molecules against inevitable laboratory manipulations.展开更多
研究了化学发光法测定山楂果肉原花青素(procyanidins of Hawthorn Sarcocarp简称HSPC)的体外抗氧化活性及其对DNA损伤的保护作用。运用邻苯三酚-鲁米诺化学发光体系测定了HSPC对超氧阴离子的清除作用,硫酸铜-邻菲啰啉-抗坏血酸-双氧水...研究了化学发光法测定山楂果肉原花青素(procyanidins of Hawthorn Sarcocarp简称HSPC)的体外抗氧化活性及其对DNA损伤的保护作用。运用邻苯三酚-鲁米诺化学发光体系测定了HSPC对超氧阴离子的清除作用,硫酸铜-邻菲啰啉-抗坏血酸-双氧水体系测定了HSPC对羟基自由基的清除作用,双氧水-鲁米诺体系测定了HSPC对体外双氧水的清除作用,采用硫酸铜-邻菲啰啉-抗坏血酸-双氧水-脱氧核糖核酸测定了HSPC对体外DNA损伤的保护作用。结果表明:当HSPC浓度为1mg/mL时,对超氧阴离子抑制率达87.7%,其半数抑制率浓度IC50值为130.8μg/mL;100μg/mL时对羟基自由基抑制率达91.7%,IC50值为61.73μg/mL;8μg/mL时对双氧水抑制率达91.6%,IC50值为0.19μg/mL;40μg/mL时对体外DNA损伤抑制率达80.7%,IC50值为22.16μg/mL。表明HSPC具有很好的体外清除活性氧和保护DNA损伤的活性。展开更多
基金National Natural Science Foundation of China(61974116)。
文摘The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with the CMOS circuit,but also acts on the protection circuit.This paper establishes a model of on-chip CMOS electrostatic discharge protection circuit and selects square pulse as the FREMP signals.Based on multiple physical parameter models,it depicts the distribution of the lattice temperature,current density,and electric field intensity inside the device.At the same time,this paper explores the changes of the internal devices in the circuit under the injection of fast rising time electromagnetic pulse and describes the relationship between the damage amplitude threshold and the pulse width.The results show that the ESD protection circuit has potential damage risk,and the injection of FREMP leads to irreversible heat loss inside the circuit.In addition,pulse signals with different attributes will change the damage threshold of the circuit.These results provide an important reference for further evaluation of the influence of electromagnetic environment on the chip,which is helpful to carry out the reliability enhancement research of ESD protection circuit.
基金supported by National Natural Science Foundation of China(82370929)Sichuan Science and Technology Program(2022NSFSC0002 and 2024NSFSC3508)+4 种基金Sichuan Province Youth Science and Technology Innovation Team(2022JDTD0021)Research and Develop Program,West China Hospital of Stomatology Sichuan University(RD03202302,RCDWJS2024-1)China Postdoctoral Science Foundation(GZB2023470)Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows(BX202317)The authors would like to thank Dr.Chenghui Li(Analytical&Testing Center,Sichuan University)for technical assistance in assisting with the particle size analysis.
文摘Unnecessary exposure to ionizing radiation(IR)often causes acute and chronic oxidative damages to normal cells and organs,leading to serious physiological and even life-threatening consequences.Amifostine(AMF)is a validated radioprotectant extensively applied in radiation and chemotherapy medicine,but the short half-life limits its bioavailability and clinical applications,remaining as a great challenge to be addressed.DNAassembled nanostructures especially the tetrahedral framework nucleic acids(tFNAs)are promising nanocarriers with preeminent biosafety,low biotoxicity,and high transport efficiency.The tFNAs also have a relative long-term maintenance for structural stability and excellent endocytosis capacity.We therefore synthesized a tFNA-based delivery system of AMF for multi-organ radioprotection(tFNAs@AMF,also termed nanosuit).By establishing the mice models of accidental total body irradiation(TBI)and radiotherapy model of Lewis lung cancer,we demonstrated that the nanosuit could shield normal cells from IR-induced DNA damage by regulating the molecular biomarkers of anti-apoptosis and anti-oxidative stress.In the accidental total body irradiation(TBI)mice model,the nanosuit pretreated mice exhibited satisfactory alteration of superoxide dismutase(SOD)activities and malondialdehyde(MDA)contents,and functional recovery of hematopoietic system,reducing IRinduced pathological damages of multi-organ and safeguarding mice from lethal radiation.More importantly,the nanosuit showed a selective radioprotection of the normal organs without interferences of tumor control in the radiotherapy model of Lewis lung cancer.Based on a conveniently available DNA tetrahedron-based nanocarrier,this work presents a high-efficiency delivery system of AMF with the prolonged half-life and enhanced radioprotection for multi-organs.Such nanosuit pioneers a promising strategy with great clinical translation potential for radioactivity protection.
文摘Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC<sub>50</sub> for lycopene was determined at 112 μg/mL which was almost partial to IC<sub>50</sub> of standard antioxidant L-ascorbic acid. The D<sub>10</sub> value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC<sub>50</sub> concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals.
基金supported by the Hi-Tech Re-search and Development Program(863)of China(No.2006AA06Z378)the National Natural Science Founda-tion of China(No.20777018)the Scientific ResearchItem of Guangxi Province Department of Education of China(No.200608LX109)
文摘The research is to test the damage to DNA of effective microorganisms(EMs)by heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+, Pb2+,and Zn2+,as well as the effects of EM bacteria on wastewater treatment capability when their DNA is damaged.The approach applied in this study is to test with COMET assay the damage of EM DNA in wastewater with different concentrations of heavy metal ions As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,Zn2+,as well as the effects of EM treated with As3+,Cd2+,Cr3+,Cu2+,Hg2+,Pb2+,and Zn2+ on COD degradin...
文摘The protective effect of DDB against carcinogen-induced DNA damage was examined in the present investigation. Preincubation of rat liver nuclei with DDB (1 mmol.L-1) resulted in 60% inhibition of binding of 3H-benzo (a) pyrene to nuclear DNA. Unscheduled DNA synthesis (UDS) induced by aflatoxin BI (10^(-7) mol.L-1) in freshly isolated rat hepatocytes was also inhibited by DDB (10^(-6)-10^(-3)mol.L-1). Oral administration of DDB at 200 mg.kg-1 once daily for 3 d induced a significant increase of liver cytosol glutathione-S-transferase and microsomal UDPG-transferase activity in mice. These results indicate that DDB is able to directly or indirectly antagonize certain carcinogen-induced DNA damages.
文摘To explore the anticancer mechanism and DNA damages of hydroxyapatite ultrofine powder (HAUFP) on lymphocytes of rats, DNA damages in W 256 sarcoma cells and lymphocytes of rats were measured by single cell gel electrophoresis (SCGE). The results showed that HAUFP damaged DNA of W 256 sarcoma cells obviously but only cause slight damage of DNA of lymphocytes in rats. It is suggested that HAUFP selectively damaged DNA of tumor cells with only mild damage of lymphocyte DNA. HAUFP has powerful anticancer effect and little genetic toxicity.
文摘The protective effect of biphenyl dimethyl dicarboxylate (DDB) on chemically induced damages was studied in isolated suspended rat hepatocytes. The experimental results showed that DDB (200μg/106 cells) efficiently protected the hepatocytes against carbon tetrachloride (CC14 10 mrnol.L-1) and D-galactosamine (1 mmol.L-1) induced damages. Membranal lipid peroxidation (malondialdehyde, MDA formation) and glutamic pyruvic transaminase (GPT) release from the hepatocytes were markedly decreased. The damage of the cell surfaces of the hepatocytes were also reduced as seen under a scanning electron microscope (SEM). Pretreatment with DDB (300 mg-kg-1) orally ameliorated the reduction of liver glycogen and blood glucose caused by ip injection of D-galactosamine (800 mg-kg-1) in mice. When normal rats were given DDB 300 mg-kg-1 once daily for 10 d, the free ribosomal protein and RNA in the liver increased significantly. These results indicate that DDB is of beneficial effects on both damaged and normal hepatocytes.
文摘Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also protect rapid DNA damage and decrease the unscheduled DNA synthesis induced by benzo(α)pyrene. The results demonstrate that GA has a potential cancer chemopreventive activity.
文摘The present study was performed to determine the influence of lipid peroxidation and perturbance of Ca2+ homeostasis on liver damage induced by 2-chloro-1, 3-butadiene (CBD) and the protective effects of vitamin E in Wistar rats. Animals were given intraperitoneally different doses (8,40 or 200 mg·kg-1 daily) of CBD for 21 days, and the following dose-dependent events were observed: liver damage, significant increase in liver lipid peroxides, and decreases in activities of erythrocytic glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). The pretreatment of rats with vitamin E (po 150 mg·kg-1) before administering CBD (iP 60 mg·kg-1 ) daily for 21 days prevented the following CBD-induced changes, the increase in serum cholylglycine (CG), hepatic LP, hepatic mitochondrion LP, hepatic oxidized glutathione (GSSG) (while the significant increase of reduced glutathione (GSH) was not affected) and the decrease in activities of erythrocytic SOD and hepatic mitochondrial calcium sequestration. These results suggest that lipid peroxidation and perturbance of Ca2+ homeostasis appear to contribute to the hepatotoxicity of CBD, and vitamin E might prevent the liver damage induced by CBD. The decrease in activities of GSH-Px and SOD in erythrocytes might be used as biomarkers for adverse effects of CBD on defense system against lipid peroxidation.
文摘To treat many types of cancer, ionizing radiation （IR） is primarily used as external-beam radiotherapy, brachytherapy, and targeted radionuclide therapy. Exposure of tumor cells to JR can induce DNA damage as well as generation of reactive oxygen species （ROS） and reactive nitrogen species （RNS） which can cause non-DNA lesions or extracellular damage like lipid perioxidation. The initial radiation-induced cell responses to DNA damage and ROS like the proteolytic processing, as well as synthesis and releasing ligands （such as growth factors, cytokines, and hormone） can cause the delayed secondary responses in irradiated and unirradiated bystander cells through paracrine and autocrine pathways.
基金supported by the Brazilian funding agencies:CNPq(Conselho Nacional de Desenvolvimento Científico e Tecnológico)CAPES(Coordenacao de Aperfeicoamento de Pessoal de Nível Superior)-No:5614112Student Agreement Program for post graduation–PEC-PG.
文摘Alzheimer’s disease（AD）is the most common type of dementia in elderly population.With a growing aging population not only in the United States but also in the worldwide,AD constitutes an emergent public health problem.
文摘In order to observe it blockers of sodium channel obsesses the neuroprotective effect on hippocampal CA 1 pyramidal cell under the condition of transient brain ischemia, the present experiment used 24 male Wistar rats aged 9 months and divided them into four groups. Lidocaine and/or furosemide were injected introcerebroventicularlly (I.C.V). Stained with H E and accounted the CA 1 pyramidal cell numbers by computer in each group suggested following findings: Although 5 μl of 2% lidocaine was injected I.C.V, the results indicated lidocaine didn't have any blockade to pyramidal cell injuries in hippocampal CA 1 area (P<0 05). In the group medicated with 2 5μl of both 2% lidocaine and 2% furosemide, the results showed that the combined approach had a blockade to injuries of pyramidal cells compared with control group (P<0 01). The present experiment indicates that the combined blockade of lidocaine and furosemide injected I.C.V. to Na + channel can prevent the injuries from hippocampal neurons owing to ischemia.
基金The work was supported by Natural Science Foundation of China(Grant No. A20077023 and C40106012
文摘In this study, two common pollutants (benzo[a]pyrene and methamidophos) in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy ( Acanthopagrus schlegeli). The fish was exposed to 2 μg/L of benzo[a]pyrene (BaP) and methamidophos, and their mixture. The assay was performed on whole blood at 2 h, 5 h, 24 h and 96 h exposure intervals. A signifi- cant increase in DNA damage was observed in each treatment with the pollutants. Additive effect of BaP and methamidophos was also found in the experiment. However, the decrease ratios of DNA damage for 5 h and 96 h exposure interals compared with 2 h and 24 h exposure ones, respectively, were noticed. This phenomenon may be explained by the function of repairing process via enzyme cytochrome P450 in the animal. Evidence of the genotoxicity of organophosphorus pesticides (OPs) and polynuclear aromatic hydrocarbons (PAHs) on marine fish are discussed in this paper.
文摘Background: There are many programs which focus on late-stage chronic kidney disease (CKD), and it is considered that further evidence needs to be generated regarding the effectiveness of the programs used before renal replacement therapy. Study Design: A cohort study. Settings & Participants: Patients over 15 years of age who had been diagnosed with CKD according to the KDOQI (Kidney Disease Outcomes Quality Initiative) guidelines and who had undergone conventional treatment (CT) or a renal protection program (RPP). These were patients of two Colombian health insurance companies. Predictors: Age, sex, marital status, comorbidities, CKD stage, and clinical indicators. Outcomes: First CKD progression, and need for renal replacement therapy (RRT). Measures: Clinical marker. Results: The RPP is structurally and functionally different from the CT. It offers the interdisciplinary management of patients, a greater number of medical appointments, and patients start to receive treatment at younger ages and at earlier stages of their condition. The clinical markers of the patients following the RPP are within adequate ranges, and their renal function is less impaired, despite the differences in basal conditions. Upon finishing the study, we found that patients who received CT had a higher risk of receiving nephrotoxic drugs and not receiving nephroprotective drugs. The explanatory variables for the first progression were age, stage, history of dyslipidemia, and hemoglobin, potassium, and albumin levels. These variables, together with glycemia levels were also valid for RRT, except for history of dyslipidemia, as it was not significant. Upon adjusting for the explanatory variables, it was found that belonging to the RPP and attending more appointments had a protective effect in the process of controlling renal damage. Limitations: A possible selection bias. Conclusions: Belonging to a structured renal protection program is an effective way to keeping the clinical markers associated with renal impairment within normal ranges.
文摘The degree and characteristics of physical degradation of macro-DNA molecules by common laboratory manipulations are reported. With linearized lambda-phage viral DNA as the model DNA, fragmentation of macro-DNA by various indispensable laboratory manipulations were investigated using a high sensitivity flow cytometric setup. Investigated manipulations included pipetting, vortexing, rocking, freeze-thawing, ultrasonication and ultrafiltration. “Exhaustive counting” of the intact lambda DNA molecules following such manipulations enabled a quantitative assessment of the resulting fragmentation, which also revealed the type of degradation reflected in the fragmentation patterns. The use of high sensitivity flow cytometry was especially suited to investigate the degradation of dilute DNA solutions that may not be suitable for analysis using traditional methods. Notable findings of this study included: the boarderline-size of DNA chains in terms of susceptibility to shear stresses by such manipulations;discernable instability of nicked DNAs;shattering-fragmentation of DNAs by freeze-thawing or ultrasonication;effectiveness of some protection media;marked “self-protection effect” of concentrated DNA solutions. These findings support and refine our traditional knowledge on how to maintain the physical integrity of macro-DNA molecules against inevitable laboratory manipulations.
文摘研究了化学发光法测定山楂果肉原花青素(procyanidins of Hawthorn Sarcocarp简称HSPC)的体外抗氧化活性及其对DNA损伤的保护作用。运用邻苯三酚-鲁米诺化学发光体系测定了HSPC对超氧阴离子的清除作用,硫酸铜-邻菲啰啉-抗坏血酸-双氧水体系测定了HSPC对羟基自由基的清除作用,双氧水-鲁米诺体系测定了HSPC对体外双氧水的清除作用,采用硫酸铜-邻菲啰啉-抗坏血酸-双氧水-脱氧核糖核酸测定了HSPC对体外DNA损伤的保护作用。结果表明:当HSPC浓度为1mg/mL时,对超氧阴离子抑制率达87.7%,其半数抑制率浓度IC50值为130.8μg/mL;100μg/mL时对羟基自由基抑制率达91.7%,IC50值为61.73μg/mL;8μg/mL时对双氧水抑制率达91.6%,IC50值为0.19μg/mL;40μg/mL时对体外DNA损伤抑制率达80.7%,IC50值为22.16μg/mL。表明HSPC具有很好的体外清除活性氧和保护DNA损伤的活性。
