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BACKGROUND:The repair process of skin trauma is complex and susceptible to infection,easy to lead to poor healing,is the current difficulty and hot spot in wound repair research,and has received extensive attention in the fields of traditional Chinese medicine and tissue engineering. OBJECTIVE:To investigate the effect of moxibustion and reduced graphene oxide/cerium oxide nanocomposite on promoting the healing of infectious wounds. METHODS:(1)Reduced graphene oxide/cerium dioxide nanocomposites with mass ratios of 2:1,1:1 and 1:2 were synthesized by hydrothermal method.The resulting composites were recorded as G2C1,G1C1 and G1C2,respectively.The photothermal properties,cytotoxicity and antibacterial properties of the three kinds of materials were tested.After taking moxa sticks,three kinds of moxibustion distances were set(3.0-3.5 cm,recorded as moxibustion 1;2.5-3.0 cm,recorded as moxibustion 2;2.0-2.5 cm,recorded as moxibustion 3).Moxibustion was applied to the surface of human skin for 10 minutes to detect the photothermal properties.The antibacterial properties of moxibustion were tested at three different distance intervals.Simultaneously,the back body surface infrared imaging of rats with different mass concentrations of G1C1 material,moxibustion(three kinds of moxibustion distances)and moxibustion 2+G1C1 material was detected.(2)Sixty male Sprague-Dawley rats were selected to model the wound of Staphylococcus aureus infection.48 hours later,they were randomly divided into 10 groups with 6 rats in each group:control group(did not receive any treatment),mupirocin group,moxibustion 2+G1C1 group,moxibustion 1 group,moxibustion 2 group,moxibustion 3 group and 60,80,100,and 120 μg/mL G1C1 groups(The G1C1 group was given 808 nm near-infrared laser irradiation for 10 min/time,and the G1C1 suspension was loaded on the wound surface before each treatment.Each group of moxibustion underwent in-situ suspension moxibustion,and the intervention time was 10 min/time.Moxibustion 2+G1C1 group was loaded with G1C1 suspension on the wound surface before each treatment,and moxibustion was suspended in situ with moxa strips,and the intervention time was 10 min/time).The frequency of treatment was 2 days once.Wound healing,wound colony count and repair were detected after 7 days of intervention. RESULTS AND CONCLUSION:(1)The three kinds of reduced graphene oxide/cerium dioxide nanocomposites had good photothermal properties,and the higher the mass concentration of the composites,the better the photothermal properties.The temperature of the moxibustion 2 group reached 47.6 ℃for 10 minutes without causing thermal damage,which was more suitable for animal experiments.The results of co-culture with NIH-3T3 cells exhibited that 60,80,and 100 μg/mL G1C1 had good biocompatibility.The results of a co-culture experiment with Staphylococcus aureus suspension displayed that G2C1,G1C1 and G1C2 had good antibacterial activity,among which G1C1 group demonstrated excellent antibacterial performance,and the antibacterial rate reached 100％when its mass concentration was 80 μg/mL.60-120 μg/mL G1C1 could effectively remove Staphylococcus aureus biofilm,and the higher the material mass concentration,the better the removal effect.Moxibustion could also effectively remove Staphylococcus aureus biofilm,and the closer the moxibustion was,the better the removal effect.(2)Compared with the control group,the wound area of the mupirocin group,moxibustion 2 group,moxibustion 2+G1C1 group and 80,100 μg/mL G1C1 groups was significantly reduced on day 7 of treatment,and the quality of wound repair was better.Mupirocin,G1C1,moxibustion and moxibustion 2+G1C1 could effectively remove the residual bacteria on the wound surface,and the higher the mass concentration of G1C1,the lower the residual bacteria.Among them,the wound repair efficiency and bacterial residue of 80 μg/mL G1C1 group and moxibustion 2 group were very similar,and the wound repair efficiency of both was better than that of mupirocin group.In addition,it was also observed that the combination of materials and moxibustion had a better ability to clear wound bacteria than that used alone.(3)The results confirm that moxibustion,reduced graphene oxide/cerium dioxide nanocomposites and their combination have good anti-infection and wound healing effects.
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BACKGROUND:Cerium(Ce)is the most abundant element among lanthanides,which is mostly in the form of ceria.The reversible transformation between Ce3+and Ce4+ ions contributes to the high redox activity of cerium.Because of its antibacterial,anti-inflammatory,osteogenic,angiogenic and anti-tumor properties,cerium has been widely used in stomatology. OBJECTIVE:To summarize the antibacterial,anti-inflammatory,osteogenic,angiogenic and anti-tumor mechanism of cerium,and to review the research status and application prospects of cerium and cerium-based materials in the modification of oral materials and the diagnosis and treatment of oral diseases in recent years. METHODS:The articles published from database inception to 2023 were retrieved from Web of Science,PubMed,CNKI and WanFang databases with the search terms"cerium,ceria,prosthodontics,prosthesis,restorative dentistry,denture,dental implant,caries,endodontics,pulpitis,periodontitis,periodontal diseases,oral cancer"in English and"cerium,ceria,prosthodontics,implant,dental caries,dental pulp,periodontitis,periodontal disease,oral cancer"in Chinese.By analyzing and reading literature for screening,according to the inclusion and exclusion criteria,73 articles were finally included in this review. RESULTS AND CONCLUSION:(1)Cerium exerts an antibacterial effect through direct contact with bacteria,oxidative stress and destroying bacterial biofilm,and exerts an anti-inflammatory function based on mimetic enzyme activity.The osteogenic and angiogenic activities of cerium involve a series of signaling pathways including ERK and Wnt signaling pathways.(2)Antibacterial,anti-inflammatory,osteogenic,and angiogenic activities allow cerium significant potential in the treatment of oral infectious diseases and regeneration of oral soft and hard tissues.However,there is still a certain gap in the application of cerium's anti-tumor properties in the oral field.(3)Due to excellent mechanical properties and a low light-transmitting property,ceria-stabilized zirconia as a dental ceramic material can be used for core ceramics,the frameworks of dental prostheses and dental implants.(4)Benefited from its biological properties,cerium-based materials have the ability to promote osseointegration and soft tissue integration,inhibit demineralization and cariogenic bacteria,facilitate regeneration of the dentin-pulp complex,lessen inflammatory response and enhance periodontal tissue regeneration.There are wide applications of cerium in surface modifications of implants and treatments of caries,pulpitis,periodontitis and oral cancers.(5)Cerium shows certain toxicity under conditions of high concentration and long-term administration.To further expand clinical applications of cerium in dentistry,biosafety and optimization of cerium-based materials need to be further explored in the future.
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BACKGROUND:The increase in multi-drug resistant bacterial infections has become a major problem in modern healthcare due to the development of bacterial resistance to antibiotics and the development of new antibacterial alternative drug materials is of great importance. OBJECTIVE:To synthesize and perform a series of characterization of a CeO2 nanoenzyme to investigate its biocompatibility and antibacterial properties against Escherichia coli. METHODS:CeO2 nanoenzymes were synthesized using a hydrothermal method.The morphology,product composition,and chemical composition were analyzed using characterization methods such as X-ray diffraction,X-ray photoelectron spectroscopy,Fourier infrared analysis,Raman spectroscopy,scanning electron microscopy,and transmission electron microscopy.The peroxide-mimetic enzyme activity of CeO2 nanoenzymes was characterized using TMB color development assay.The toxic effect of CeO2 nanoenzymes at different concentrations(10,25,and 50 μg/mL)on mouse fibroblast L929 cells was evaluated using the CCK-8 assay.The antibacterial properties of CeO2 nanoenzymes against Escherichia coli under different conditions were evaluated using the plate coating method.Changes in intra-bacterial reactive oxygen species after treatment with different conditions were detected using a reactive oxygen species detection kit. RESULTS AND CONCLUSION:(1)The morphology of the synthesized CeO2 nanoparticles was rod-shaped,with Ce3+ accounting for 29.87%of the total Ce3+/Ce4+ and an average grain size of 7.4 nm.In a slightly acidic environment containing TMB and pH=5.5,CeO2 nanoenzymes mixed with H2O2 showed excellent peroxidase activity,but did not show peroxidase simulated activity at pH=7.4.(2)There was no statistically significant difference in the toxic effects of CeO2 nanoparticles at various mass concentrations on mouse fibroblast L929 cells.(3)In a slightly acidic environment at pH 5.5,Escherichia coli was inhibited to a certain extent in the presence of CeO2 nanoenzyme alone at a concentration of 10 μg/mL,with a decrease in CFU results of about 0.5 log(P＜0.01);in a slightly acidic environment containing 50 μmol/L H2O2,CeO2 nanoenzyme showed excellent antibacterial effects against Escherichia coli,with a decrease in Escherichia coli CFU results of by about 1.5 log(P＜0.001).After CeO2 nanoenzymes interacted with Escherichia coli,the level of reactive oxygen species in Escherichia coli increased(P＜0.05);after CeO2 nanoenzymes interacted with Escherichia coli together with H2O2,the level of reactive oxygen species in Escherichia coli increased significantly(P＜0.001).(4)The results show that the CeO2 nanoenzymes have good biocompatibility,are inherently antibacterial,and can exhibit peroxidase activity in a slightly acidic environment containing low concentrations of H2O2,and generate reactive oxygen species to kill bacteria,thus showing excellent antibacterial effects.
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@#Objective To study the effect of nano-ceria on doxorubicin-induced cardiotoxic injury and its effect on P53 gene expression,and to explore the mechanism of nano-ceria on doxorubicin-induced cardiotoxic injury.Methods H9C2 myocardial cells were cultured and randomly divided into five groups:control group,model group(1μmol/L adriamycin),nano-cerium oxide group(10μg/ml nano-cerium oxide),experimental group(1μmol/L adriamycin +10μg/ml nano-cerium oxide),and positive control group(1μmol/L adriamycin+10μmol/L dexperimine).The adriamycin induced cardiotoxicity model was established,and the viability of myocardial cells was measured by CCK-8 method.The contents of lactate dehydrogenase(LDH)and malondialdehyde(MDA)in myocardial cells were detected by biochemical method.The levels of reactive oxygen(ROS)and the apoptosis rate in myocardial cells were detected by flow cytometry.The expressions of Bax,Bcl-2 and P53 proteins in myocardial cells were detected by Western blot.Results Compared with the control group,the cell viability was decreased in the model group,the cell LDH and MDA contents were increased,the intracellular ROS level and apoptosis rate were increased,the expressions of Bax and P53 proteins were increased,and the expression of Bcl-2 protein was decreased,and the ratio of Bcl-2/Bax was decreased(all P<0.001).Compared with the model group,the experimental group showed increased cell viability,decreased cell LDH and MDA contents,decreased cell ROS content and apoptosis rate,decreased Bax and P53 protein expressions,and increased Bcl-2 protein expression,and the Bcl-2/Bax ratio was increased(all P<0.001).Conclusion Ceria nanoparticles can effectively prevent adriamycin-induced cardiotoxic injury,and its effect may be related to the down-regulation of P53 gene to inhibit cardiomyocyte apoptosis.
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Objective To develop an unmanned aerial vehicle (UAV)-borne radiation monitoring system with high detection efficiency and nuclide identification ability for airborne monitoring in nuclear emergency. Methods The UAV-borne CeBr3 radiation monitoring system was composed of four cerium bromide (CeBr3) crystal detectors coupled with silicon photomultipliers (SiPMs) and other components including integrated modules, intelligent electronic devices, and new composite materials. Results According to various performance tests on the system, the crystal energy resolution was better than 5% (@0.662 MeV), the peak drift of the energy spectrum was within ±1 channel, the linear fit of energy was 0.99997, the change in the count rate of each energy window during 12 h long-term measurement was less than 5%, and the detection efficiency was higher compared with that of NaI (Tl) detectors of the same volume. Conclusion Through ground point source testing and theoretical calculation, the system has reliable ability to identify radionuclides, which can be used in nuclide identification and the preparedness and response for nuclear and radiation emergencies.
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Objective:To establish an antimony cerium catalytic spectrophotometric method for determination of iodine in water (referred to as the new method).Methods:Using the fading reaction principle of iodine catalyzed kinetics of antimony cerium to determine the iodine content in water. Methodological evaluations were conducted on the linear relationship, quantitative detection limit, precision, and accuracy (determination of national water iodine first level standard substances GBW09113f, GBW09114f, and addition recovery experiments) of the new method within the range of 0 to 100 μg/L iodine mass concentration. And the method was compared with the determination results of water iodine by arsenic cerium catalytic spectrophotometry recommended by the national iodine reference laboratory (NRL).Results:Within the range of 0 - 100 μg/L iodine mass concentration, the curve correlation coefficient of the new method was greater, and | r| > 0.999 0, and the quantitative detection limit was 0.15 μg/L (the sampling volume was 1 ml), the relative standard deviation of the detection precision of water samples with low, medium and high iodine mass concentrations were less than 2%. The new method had determined the average values of national water iodine first level standard substances GBW09113f and GBW09114f were 8.32 and 54.54 μg/L, respectively, all within the standard value range. The recovery range of standard addition was 92.6% - 99.2%, and the total average recovery was 96.4%. Compared with the NRL recommended method, the difference was not statistically significant ( t = 0.99, P > 0.05). Conclusion:The new method does not require the use of highly toxic substance arsenic trioxide, has high reaction sensitivity and accuracy, and is suitable for the promotion and use of water iodine detection.
الملخص
Objective:To study the application of ammonium cerium sulfate spectrophotometry for determination of iodide in water.Methods:Ammonium cerium sulfate spectrophotometry was used to determine the iodine content of tap water and source water in the range of 0 - 20 and 0 - 200 μg/L iodine concentration. The effect of the method was verified in terms of linear range, detection limit, precision and accuracy.Results:In the range of 0 - 20 and 0 - 200 μg/L iodine concentration, the absolute values of linear correlation coefficients were > 0.999 0; the detection limits were 0.18 and 1.02 μg/L, respectively; the coefficient of variation of low, medium and high iodine concentrations in tap water and source water was less than 5%. In the range of 0 - 20 μg/L iodine concentration, the spiked recovery rates of tap water and source water were 90.33% - 110.46% and 92.21% - 102.82%, respectively; in the range of 0 - 200 μg/L iodine concentration, the spiked recovery rates of tap water and source water were 90.14% - 102.62% and 91.36% - 106.18%, respectively. The national first level standard materials GBW09113g and GBW09114g were tested, and the results of water iodine determination were within the given range of the standard materials.Conclusion:Ammonium cerium sulfate spectrophotometry has a wide linear range, high accuracy, and good precision, making it suitable for widespread application in grassroots areas.
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Objective:To study the application of antimony cerium catalytic spectrophotometry using a fully automatic biochemical analyzer (hereinafter referred to as this method) in the determination of water iodine.Methods:Based on the principle of antimony cerium reoxidation reduction reaction catalyzed by iodine, the iodine content in water was determined in the range of 0 - 100 μg/L iodine mass concentration. The detection limit, precision and accuracy (determination of standard substances GBW09113j and GBW09114j for iodine composition analysis in water and the experiment of standard recovery) of this method were verified. This method was compared with the arsenic and cerium catalytic spectrophotometry recommended by the National Reference Laboratory for Iodine Deficiency Disorders.Results:Within the range of 0 - 100 μg/L iodine mass concentration, the qualitative and quantitative detection limits of this method were 0.81 and 2.70 μg/L, respectively (sampling quantity was 35 μl). In the precision experiment, the relative standard deviation of water samples with different iodine mass concentrations ranged from 1.2% to 4.0%. The determination results of the standard substances GBW09113j and GBW09114j for iodine composition analysis in water were both within the given standard value range. The standard recovery rates of water samples with low, medium and high iodine mass concentrations ranged from 101.0% to 106.0%, and the total average standard recovery rate was 103.2%. The results of the method comparison experiment showed that there was no statistically significant difference in the results of water iodine determination between the two methods ( t = - 0.78, P = 0.779). Conclusion:This method has a low detection limit, high precision and good accuracy, making it suitable for the detection of large quantities of samples in the monitoring of iodine deficiency disorders.
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The typical hallmark of tumor evolution is metabolic dysregulation. In addition to secreting immunoregulatory metabolites, tumor cells and various immune cells display different metabolic pathways and plasticity. Harnessing the metabolic differences to reduce the tumor and immunosuppressive cells while enhancing the activity of positive immunoregulatory cells is a promising strategy. We develop a nanoplatform (CLCeMOF) based on cerium metal-organic framework (CeMOF) by lactate oxidase (LOX) modification and glutaminase inhibitor (CB839) loading. The cascade catalytic reactions induced by CLCeMOF generate reactive oxygen species "storm" to elicit immune responses. Meanwhile, LOX-mediated metabolite lactate exhaustion relieves the immunosuppressive tumor microenvironment, preparing the ground for intracellular regulation. Most noticeably, the immunometabolic checkpoint blockade therapy, as a result of glutamine antagonism, is exploited for overall cell mobilization. It is found that CLCeMOF inhibited glutamine metabolism-dependent cells (tumor cells, immunosuppressive cells, etc.), increased infiltration of dendritic cells, and especially reprogrammed CD8+ T lymphocytes with considerable metabolic flexibility toward a highly activated, long-lived, and memory-like phenotype. Such an idea intervenes both metabolite (lactate) and cellular metabolic pathway, which essentially alters overall cell fates toward the desired situation. Collectively, the metabolic intervention strategy is bound to break the evolutionary adaptability of tumors for reinforced immunotherapy.
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Drought is a common limiting factor affecting rice yield and quality. Cerium oxide nanoparticles(nanoceria) have been widely reported to improve crop stress tolerance. However, the effects and mechanisms of nanoceria on rice drought tolerance are still unknown. The aim of this study is to investigate whether nanoceria can improve rice drought tolerance by modulating reactive oxygen species(ROS) homeostasis and nitric oxide(NO) levels. Our results showed that compared with no-nanoparticle treatment, nanoceria significantly increased the fresh weight of rice seedlings under drought stress(19%, P < 0. 05). Also, under drought stress, the ROS level of rice leaves treated with nanoceria was significantly lower(82%, P < 0. 05) than leaves treated with buffer. The leaf NO level after nanoceria treatment, however, is significantly higher(46%, P < 0. 05) than that with no-nanoparticle treatment under drought stress. Moreover, compared with control plants, nanoceria maintained better membrane integrity in rice leaf cells under drought stress, showing a 70% decrease(P < 0. 05) in dead leaf cells. This study explores the mechanisms underlying nanoceria’s improved rice drought tolerance by affecting ROS and NO levels, which not only further enriches our knowledge about the interaction between nanoparticles and crops under abiotic stress but also gives more support on the sustainable development of nano-enabled agriculture.
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Objective:To establish a method for automatic determination of iodine level in salt by arsenic-cerium catalytic spectrophotometry using an iodine element detector (hereinafter referred to as this method), and to provide reference for in-depth study of salt iodine detection technology.Methods:This method was used to determine the iodine level in salt, and the linear range, detection limit, precision, and accuracy (determination of salt iodine standard substance GBW10006y and GBW10007y, and addition recovery experiment) of this method were determined. The iodine level of 35 salt samples was determined by this method and redox titration method recommended by the national standard, and the results were compared.Results:This method had a good linear relationship within the range of 50 - 600 μg/L standard curve, the absolute value of the correlation coefficients was > 0.999 0, and the detection limit was 5.0 mg/kg. The relative standard deviation of iodine concentration in salt samples with low, medium and high iodine concentrations were all < 6.0%. The determination results of salt iodine standard substance GBW10006y and GBW10007y were within the given value ranges; three iodine concentrations (6.0, 10.0 and 30.0 mg/kg) were added to the salt samples, with an average recovery rate of 96.7% to 105.0%, and a total average recovery rate of 100.9%. The method comparison experiment showed that there was no statistically significant difference between the salt iodine determination results of this method and the redox titration method ( t = - 1.54, P = 0.132). Conclusion:This method has the advantages of high accuracy, good precision and wide linear range in determining salt iodine, and is suitable for the detection of large quantities of samples in salt iodine monitoring.
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Objective:To establish a method for determination of iodine in salt by arsenic-cerium catalytic spectrophotometry.Methods:The content of iodine in salt was detected by arsenic-cerium catalytic spectrophotometry with an automatic iodine analyzer. The standard curve linearity, detection limit, precision and accuracy of the method were evaluated. The iodine content of 20 edible salt samples was detected by the newly established method and direct titration, and the results were compared.Results:In the range of 0 - 150 μg/L standard curve, the correlation coefficient ( r) = - 0.999 9, and the detection limit was 1.4 mg/kg. The average iodine contents of iodine composition analysis standard materials GBW10006z and GBW10007z were 12.2 and 22.8 mg/kg ( n = 6), respectively, which were all within the given standard value ranges, and the relative standard deviations ( RSD) were 2.04% and 2.33%, respectively. Iodine composition analysis standard materials GBW10006b, GBW10007b, GBW10006v, GBW10007v, GBW10006z and GBW10007z measurement results (12.0, 24.6, 12.6, 22.8, 12.3, 23.2 mg/kg, n = 2) were all within the given standard value ranges, with good quality control. The iodine content of 20 edible salt samples was detected by arsenic-cerium catalytic spectrophotometry and direct titration, respectively, and the difference was not statistically significant ( t = 1.99, P = 0.060). Conclusion:Arsenic-cerium catalytic spectrophotometry has the characteristics of good linear relationship, low detection limit, good precision and high accuracy in determination of salt iodine content, which is suitable for popularization and application.
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Objective: To develop and validate new, selective spectrophotometric colorimetric analytical methods for the quantification of methimazole in its pure form and in its pharmaceutical preparations. Methods: Method A is based on the oxidation of methimazole with potassium permanganate in alkaline medium, the manganate ion produced was measured at λmax= 610 nm. Method B is a kinetic determination of methimazole using fixed-time method based on the oxidation of methimazole using known excess of cerium (IV) nitrate in acidic medium and assessing the unreacted Ce (IV) by adding a fixed amount of methyl orange and measuring the absorbance of the resultant solution at λmax=507 nm which is equivalent to the unreacted methyl orange. The reaction conditions and analytical parameters are investigated and optimized. Method validation was carried out according to ICH guidelines in terms of linearity, LOD, LOQ, precision, and accuracy. Results: Beer’s law is obeyed in the range of 1.50–15.00 μg/ml for method A and 0.25–3.00 μg/ml for method B. The developed methods were subjected to the detailed validation procedure. The proposed spectrophotometric methods were applied for the determination of the methimazole in its pure form and in its pharmaceutical formulation. The percentage recoveries were found to be 100.82 % and 99.85 % in the pharmaceutical formulation for the two proposed methods, respectively. Conclusion: Both developed spectrophotometric methods, considered as green analytical chemistry, were found to be novel, highly selective and can be applied for the quality control of methimazole in its pure form and in its pharmaceutical formulation based on the simplicity, applicability of the parameters, accessibility of the reagents employed and reasonably low time of analysis.
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OBJECTIVE: To study the effect of nano-cerium oxide on the early development of zebrafish embryos. METHODS: The well-developed zebrafish embryos were randomly divided into the control group and the 50, 100, 200, 400 and 800 mg/L dose groups, with 40 embryos in each group. The dose groups were treated with nano-cerium oxide at the corresponding mass concentration for 5 days. The control group received no treatment. The death and malformation of embryos were observed. The heart rate of zebrafish embryos was recorded using confocol microscope. The protein expression of microtubule-associated protein 1 light chain 3(LC3) and cleaved Caspase-3 and were observed by Western blot technology. RESULTS: The death and embryonic malformation rate of zebrafish embryos increased with the increase of doses, showing statistical significance(P<0.01). The heart rate of the 800 mg/L dose group was decreased compared with the control group [(77±8) vs(93±4) beats/min, P<0.01]. There was no statistical significant difference in LC3-Ⅱ protein expression in each groups(P>0.05). The cleaved Caspase-3 protein expression increased in all dose groups compared with the control group(P<0.05). The cleaved Caspase-3 protein expression in the 200 mg/L dose group was higher than that in the 50 mg/L dose group(P<0.05). CONCLUSION: The nano-cerium oxide may induce cell apoptosis, causing toxic effect in early development of zebrafish embryos.
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Objective To investigate the effects of cerium oxide nanoparticles of different sizes on the number and constructions of immune cells in peripheral blood of mice after X-ray irradiation. Methods Mice were randomly divided into 4 groups according to body weight layer and the weight of each mouse was weighed. All mice were divided into 6 groups according to weight from high to low, and there were 4 mice in each group. Then 1 mouse was randomly taken from each group to form the control group. Model group, 5 nm and 25 nm cerium oxide nanoparticles groups were formed in turn. There were 6 mice in each group. The mice in model group and cerium oxide nanoparticles administration groups were irradiated once with 3 Gy of X-rays. The mice in cerium oxide nanoparticles groups began to be intraperitoneally administrated once a day with 10 μg 5 nm or 25 nm cerium oxide nanoparticles per kilogram body weight on the 4th day before irradiation and once every other 2 days after irradiation. The mice in the control group and model group were intraperitoneally administrated with 0.9 % saline. The mice were killed on the 10th days after irradiation. White cells count (WBC) and classification in peripheral blood were detected by using automatic globulimeter, and lymphocyte subsets were analyzed by using flow cytometry. Results Compared with the control group, the number of WBC, neutrophil granulocytes, monocytes, lymphocytes, total T lymphocytes, CD4+and CD8+T lymphocytes and the percentages in the model group were decreased (all P＜0.05), and percentages of the lymphocytes, B cells and NK cells and ratio of CD4 to CD8 were increased in model group (all P＜ 0.05). Compared with the model group, the above parameters except percentages of T lymphocytes, CD4+and CD8+T lymphocytes were improved in mice of 5 nm cerium oxide nanoparticle group (all P ＜0.05). Compared with the control group, the number of WBC and lymphocytes were decreased in the 5 nm cerium oxide nanoparticle group (P＜0.05), and there were no significances in other parameters compared with the control group (all P ＞0.05). Compared with the control group, the number of WBC and lymphocytes, the number and percentages of T lymphocytes, CD4+and CD8+T lymphocytes and the percentages were decreased (all P＜ 0.05), and percentage of NK cells and ratio of CD4 to CD8 were significantly increased in 25 nm cerium oxide nanoparticles group (all P＜ 0.05). The number of lymphocytes and CD8+T lymphocytes in 25 nm cerium oxide nanoparticles group was lower than that in 5 nm cerium oxide nanoparticles group (all P ＜ 0.05). Conclusions The effects of cerium oxide nanoparticles of different sizes on the immune cells of mice after X-ray irradiation are different, and 5 nm cerium oxide nanoparticle is superior to 25 nm cerium oxide nanoparticle.
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Objective To establish a catalytic spectrophotometric method for determination of iodine in water using the same arsenious acid solution and ceric ammonium sulfate solution as those used in the 2016 version standard method for determination of urinary iodine,and to meet the needs of wide concentration range of water iodine detection.Methods After pretreatment of the water sample with the effective chlorine of sodium dichloroisocyanurate solution for eliminating the interference of reducing substances at room temperature,the concentration of iodine in water was determined by arsenic cerium catalytic spectrophotometry using the same 0.025 mol/L arsenious acid solution and 0.025 mol/L ceric ammonium sulfate solution as those used in the 2016 version standard method for determination of urinary iodine.The linear relationship of the standard curve and the linear rang of different iodine concentration range (0-100,0-400,0-800μg/L),the detection limit,the precision and the accuracy of the sample were tested.Results The calibration relation of C =a + blgA (C:iodine concentration,A:measuring absorbance) in the new method existed when arsenic cerium catalytic reaction was kept at a certain stable temperature ranging from 15 ℃ to 30 ℃ in certain stable reacting time.The linear correlative coefficients absolute value of different iodine concentration range (0-100,0-400,0-800 μg/L) were all greater than 0.999 0,corresponding to the water iodine detection limits were 0.3 μ,g/L (sample volume of 0.80 ml),1.2 μg/L (sample volume of 0.20 ml),and 2.2.μg/L (sample volume of 0.10 ml),respectively.The coefficients of variation (CV) of the three different iodine concentration range were all below 1.0％ (n =6).The iodine recovery rate range of a total of 10 different water samples in these three different concentration range was 95.8％-98.7％,98.3％-103.7％ and 98.5％-104.5％,and the average recovery rate was 97.6％,100.4％ and 102.4％,respectively.In the range of these three different standard curves,water iodine standard materials GBW09114c,GBW09114a and GBW09113c were measured.The relative errors between the results and the given values were ＜ 3.0％,which were in the range of uncertainty of the given value.Conclusion This method verified by methodology experiments has wide linear range,high precision,accuracy,and anti-interference ability,good reproducibility,and is easy to operate,with reduced amount of arsenic waste,reduced environmental pollution,and is suitable for application in different areas to determine water iodine.
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Objective To establish a arsenic cerium catalytic rate method for determination of urinary iodine,and increase the linear range of urinary iodine determination.Methods Standard series and urine samples after digestion treatment,were tested using dynamics function of spectrophotometer to record the curve of absorbance value (A) change with time (t) during arsenic cerium catalytic reaction for each measurement system,choice (A1,t1) and (A 2,t2) on this curve and calculating the reaction rate (v),v =(lgA1-lgA2)/(t2-t1).Through the determination of the standard series it could calculate regression equation of iodine concentration (C) with X:C =a ± bX,X =1 000 (v-v0),and the v0 is the reaction rate of reagent blank.Results (① C and X were positively correlated.The standard series linear range was 0-1 200 pμg/L and correlation coefficient r was higher than 0.999 1.The minimum detection limit was 3.9 μg/L (0.25 ml urine).②)Precision:5 urine samples (A,B,C,D,E) were selected within the range of 0-1 200 μg/L and the measured value were (72.3 ± 2.7),(148.2 ± 5.2),(210.5 ± 4.4),(562.7 ± 6.8),and (899.3 ± 8.0) μg/L.The relative standard deviation (RSD) was between 0.9％-3.8％.(③)Accuracy:4 samples (A,B,C,D) were measured for standard addition recovery test,recovery was between 94.2％-107.2％;urinary iodine standard material [the given values were (67.9 ± 9.0),(142.0 ± 10.0),(195.0 ± 10.0),(558.0 ± 17.0),(885.0 ± 28.0) μg/L] were determined and the results were in the range of uncertainty of the standard material.④Method contrast:with the national health standard method (method for determination of iodine in urine by arsenic cerium catalytic spectrophotometry) to determinate 120 urine samples,the results showed that there were 60 urine samples within 0-300 μg/L,60 urine samples were more than 300 μg/L.Then rate method was used to test the 120 urine samples.For the 60 samples within the scope of 0-300 μg/L,the determination results of the two methods were positively correlated (r =0.994,P ＜ 0.01);the results of the rate method were lower than those of the standard method and the difference was statistically significant (t =2.047,P ＜ 0.05).But the average deviation was only 2.1 μg/L,for the determination of urine iodine there was no practical significance;for the 60 samples higher than 300 μg/L,the determination results of the two methods were positively correlated (r =0.993,P ＜ 0.01) and the difference was not statistically significant (t =-1.092,P ＞ 0.05).Conclusions Arsenic cerium catalytic rate method has increased the linear range of urinary iodine determination.Using this method,the vast majority samples can be tested directly without dilution,thereby reducing the workload for determination of urine iodine.
الملخص
Objective To screen the suitable sample digestion method for measuring iodine in serum by arsenic cerium catalytic spectrophotometric method , and to carry out the methodology test for the newly developed arsenic cerium catalytic spectrophotometry for determination of iodine in serum .Methods Methodology evaluation.Experimentswere on the sample on the sample digestion method of serum iodine with several common digestive agents . After digestion treatment , the concentration of iodine in serum was determined by arsenic cerium catalytic spectrophotometry .The linearity and linear range of the standard curve, detection limit, precision, recovery rate and anti -interference ability of the newlydeveloped arsenic cerium catalytic spectrophotometry were tested .Results Sample pretreatment method included in the newly developed arsenic cerium catalytic spectrophotometry was selected as follows: perchloric acid -sodium chlorate solution was used as the digestive agent to digest 120 min at 130℃.The calibration relation of C =a+blgA( C: iodine concentration ,A: measuring absorbance ) of the newly developed method existed when arsenic ceriumcatalytic reaction was kept at a certain stable temperature range from 13℃ to 30℃ and in certain stable reacting time .The linear range of the calibration curvewas 0 -300 μg/Land the linear correlative coefficient was -0.9996 --0.9999.The intra assay coefficients of variation ( CVs ) were 0.70%,0.70%and 0.74%(n=6), and the inter assay CVs were 0.57%, 0.51% and 0.57% (n=6) for 3 serum samples.The average recovery was 97.9% with a range from 92.3% to 105.8% for 3 serum samples.Conclusions The newly developed arsenic cerium catalytic spectrophotometry has good precision and accuracy .The sample digestion agent is easy to be prepared and reserved , and the instrument is simple and easy to be operated .The method can be widely used as a reliable technique for measuring iodine in serum.
الملخص
Objective By studying the variation of individual urinary iodine concentration due to different ways of urine sample collection to optimize it for standard clinical evaluation.Methods Totally 20 healthy adults were recruited and their urine samples were collected as a random urine sample within 1 day,the 24 hour urine and morning urine samples within 5 successive days,respectively.The coefficient of variation in each group was calculated.Paired t test was used to compare the results of 24 hour urine with the results of random urine and that of morning urine samples,respectively.Results The range of individual coefficient of variation for random urine sample within one day was 12.5％-57.4％,while most of the coefficients of variation were around 30.39％.In contrast,the individual coefficients of variation of morning urine sample and 24 hour urine results within 5 days were 5.4％-26.0％ and 3.4％-16.6％ and most of them were at about 11.74％ and 7.91％.The paired t test showed that the results of random urine sample were significantly different compared with that of 24 hour urine (t =-4.231,P ＜ 0.05).On the other hand,there was also significant difference for the results of morning urine compared with that of 24 hour urine (t =3.884,P ＜ 0.05).Conclusion This study suggests that 24 hour urine is the most appropriate way of sample collection for individualized detection of urinary iodine.
الملخص
OBJECTIVE: To observe the in vivo metabolism and distribution characteristics of nano-cerium oxide( nanoCeO_2) in rats,and to explore the radio-protective effect of nano-CeO_2. METHODS: i) A total of 18 specific pathogen free( SPF) SD rats were randomly divided into 3 groups. Rats of experiment group and CeO_2 blood group were gavaged with1. 0 g/kg body weight( bw) nano-CeO_2 suspension. Rats of control group were gavaged with double distilled water( DDW)in equal volume. At different time-points after treatment,venous blood was collected from the rats' eye socket in CeO_2 blood group,meanwhile urine and excrement of rats of experiment group were also collected. Organ and tissue samples of experiment group and control group were collected 24. 0 hours after treatment. The concentrations of cerium in biological samples were detected by inductively coupled plasma mass spectrometry. ii) A total of 72 SPF BALB/c mice were randomly divided into 6 groups. Mice of low-,medium-and high-dose groups were gavaged with 100,300 and 900 mg/kg bw nano-CeO_2 suspension respectively. Mice of negative control group,irradiation control group and drug positive control group were gavaged with DDW in equal volume once daily. After 14 days,mice of the other 5 groups were exposed by60Coγ-rays once with 3. 5 Gy( 1 Gy/min) except the negative control group. Mice of drug positive control group were given intraperitoneal injection with 200 mg/kg bw amifostine half an hour before irradiation. After exposure,mice were treated by the above gavages once daily. After 3 and 8 days,6 mice were randomly selected to collect the peripheral blood for the count of white blood cell( WBC) and lymph cell measuring. RESULTS: i) The cerium concentration in blood reached peak value in 4. 0 hours after exposure of nano-CeO_2,and the cerium concentration of urine and excrement reached maximum in8. 0 hours after exposure. After 24. 0 hours of exposure,the cerium concentration of brain in experiment group was higher than that of control group( P < 0. 05). Among the experiment group,the cerium concentrations of sternum,duodenum and brain were higher than that of kidney and heart( P < 0. 05),meanwhile the cerium concentrations of thymus and lung were higher than that of kidney( P < 0. 05). ii) There was no statistical difference in interactive effect of WBC count and lymph cell counts between nano-CeO_2 exposure ways and time( P > 0. 05). The WBC counts of the low-and medium-dose groups were lower than those of the negative control group and the drug positive control group( P < 0. 05). The WBC count of high-dose group was lower than those of irradiation control group,drug positive control group and medium-dose group( P <0. 05). The lymph cell counts of the 3 dose groups were lower than that of drug positive control group( P < 0. 05).CONCLUSION: The nano-CeO_2 is mainly cumulated in organs such as sternum,duodenum,brain,thymus and lung. After induced by radiation,nano-CeO_2 has a certain degree of promotion role in increasing the WBC counts.