Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pa...Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.展开更多
A method was developed on a gas chromatograph coupled to a triple quadrupole mass spectrometer(GC-MS/MS) for trace level determination of polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and dioxin-like polych...A method was developed on a gas chromatograph coupled to a triple quadrupole mass spectrometer(GC-MS/MS) for trace level determination of polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and dioxin-like polychlorinated biphenyls(DL-PCBs) in food and feed. The results demonstrated good sensitivity and repeatability for PCDD/Fs and DL-PCBs at an extremely low level(10 pg mL^(-1) for 2,3,7,8-TCDD/F), as well as wide linear response of over 3 or 4 orders of magnitude in concentration ranges; 0.5–200 ng mL^(-1) for PeCDD/F and 0.2–2000 ng mL^(-1) for DL-PCBs. The method detection limits for PCDD/Fs and DL-PCBs were in the range from 0.018–0.17 pg g^(-1) to 0.13–0.36 pg g^(-1), respectively. The performance of the GC-MS/MS for food and feed sample analysis showed high precision and accuracy compared to the high resolution gas chromatograph/high resolution mass spectrometer. The results indicated the feasibility of GC-MS/MS as a confirmatory method for the measurement of PCDD/Fs and DL-PCBs in food and feed as required by European Union legislation.展开更多
Purpose:To investigate the epidemiology,causative pathogen antibiotic susceptibility,and mortality risk factors of bloodstream infection(BSI)in patients with hematological malignancies(HMs).Methods:Single-center retro...Purpose:To investigate the epidemiology,causative pathogen antibiotic susceptibility,and mortality risk factors of bloodstream infection(BSI)in patients with hematological malignancies(HMs).Methods:Single-center retrospective analysis of BSI cases in patients with HMs in a Chinese tertiary hospital from 2012-2019.Results:Among 17,796 analyzed admissions,508 BSI episodes(2.9%;95%confidence interval:2.6%-3.2%)were identified.Of 522 resulting isolates,326(62.5%)were Gram-negative,173(33.1%)were Gram-positive.The BSI incidence among patients with different HMs(severe aplastic anemia:6.7%;acute leukemia:6.2%;myelodysplastic syndrome:3.2%;multiple myeloma:1.3%;and lymphoma:1.0%)differed significantly(p<0.001).The BSI incidence was significantly higher in the hematopoietic stem cell transplantation(HSCT)group(10.2%)than in the non-HSCT group(2.5%;p<0.001).Escherichia coli(30.7%,160/522)was the most common pathogen,followed by Coagulase-negative staphylococci(19.4%,101/522)and Klebsiella pneumoniae(10.0%,52/522).,The rates of imipenem resistance for E.coli,K.pneumoniae,Pseudomonas aeruginosa,and Acinetobacter baumannii were 6.4%,15.0%,27.8%,and 79.0%,respectively.All the Gram-positive pathogens were linezolid susceptible.Three vancomycin-resistant Enterococcus species were isolated.The overall 14-day mortality was 9.8%(95%confidence interval:7.2%-12.4%).A multivariate analysis showed that HM subtype severe aplastic anemia,A.baumannii,and malignancy non-remission were independent 14-day mortality risk factors.Conclusions:Gram-negative bacteria were the most common pathogens,with E.coli as the predominant strain,causing BSIs in HM patients.A carbapenem-resistant A.baumanni with a high mortality rate in HM patients made empirical antimicrobial choice a highly challenging issue.展开更多
The concentrations and geographical distribution of hexabromocyclododecane （HBCD） were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow ...The concentrations and geographical distribution of hexabromocyclododecane （HBCD） were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection （LOD） to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of t-IBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that y-HBCD dominated in most of the sediment samples, followed by ct- and [3-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively.展开更多
Quartz particles are a toxic component of airborne paniculate matter（PM）.Quartz concentrations were analyzed by X-ray diffraction in eighty-seven airborne PM samples collected from three locations in Beijing before,...Quartz particles are a toxic component of airborne paniculate matter（PM）.Quartz concentrations were analyzed by X-ray diffraction in eighty-seven airborne PM samples collected from three locations in Beijing before,during,and after the Asia-Pacific Economic Cooperation（APEC） Leaders＇ Meeting in 2014.The results showed that the mean concentrations of quartz in PM samples from the two urban sites were considerably higher than those from the rural site.The quartz concentrations in samples collected after the APEC meeting,when the pollution restriction lever was lifted,were higher than those in the samples collected before or during the APEC meeting.The quartz concentrations ranged from 0.97 to 13.2 μg/m^3,which were among the highest values amid those reported from other countries.The highest quartz concentration exceeded the Californian Office of Environmental Health Hazard Assessment reference exposure level and was close to the occupational threshold limit values for occupational settings.Moreover,a correlation analysis showed that quartz concentrations were positively correlated with concentrations of pollution parameters PM10,PM2.5,SO2 and NOx,but were negatively correlated with O3 concentration.The results suggest that the airborne quartz particles may potentially pose health risks to the general population of Beijing.展开更多
基金supported by the National Natural Science Foundation of China,No.30360100,30760234,30860260,81160373,81360458
文摘Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.
基金supported by the National Natural Science Foundation of China(21477156,21477155,41276195)Chinese Academy of Sciences(XDB14010100)the National Basic Research Program of China(2015CB453101)
文摘A method was developed on a gas chromatograph coupled to a triple quadrupole mass spectrometer(GC-MS/MS) for trace level determination of polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/Fs) and dioxin-like polychlorinated biphenyls(DL-PCBs) in food and feed. The results demonstrated good sensitivity and repeatability for PCDD/Fs and DL-PCBs at an extremely low level(10 pg mL^(-1) for 2,3,7,8-TCDD/F), as well as wide linear response of over 3 or 4 orders of magnitude in concentration ranges; 0.5–200 ng mL^(-1) for PeCDD/F and 0.2–2000 ng mL^(-1) for DL-PCBs. The method detection limits for PCDD/Fs and DL-PCBs were in the range from 0.018–0.17 pg g^(-1) to 0.13–0.36 pg g^(-1), respectively. The performance of the GC-MS/MS for food and feed sample analysis showed high precision and accuracy compared to the high resolution gas chromatograph/high resolution mass spectrometer. The results indicated the feasibility of GC-MS/MS as a confirmatory method for the measurement of PCDD/Fs and DL-PCBs in food and feed as required by European Union legislation.
文摘Purpose:To investigate the epidemiology,causative pathogen antibiotic susceptibility,and mortality risk factors of bloodstream infection(BSI)in patients with hematological malignancies(HMs).Methods:Single-center retrospective analysis of BSI cases in patients with HMs in a Chinese tertiary hospital from 2012-2019.Results:Among 17,796 analyzed admissions,508 BSI episodes(2.9%;95%confidence interval:2.6%-3.2%)were identified.Of 522 resulting isolates,326(62.5%)were Gram-negative,173(33.1%)were Gram-positive.The BSI incidence among patients with different HMs(severe aplastic anemia:6.7%;acute leukemia:6.2%;myelodysplastic syndrome:3.2%;multiple myeloma:1.3%;and lymphoma:1.0%)differed significantly(p<0.001).The BSI incidence was significantly higher in the hematopoietic stem cell transplantation(HSCT)group(10.2%)than in the non-HSCT group(2.5%;p<0.001).Escherichia coli(30.7%,160/522)was the most common pathogen,followed by Coagulase-negative staphylococci(19.4%,101/522)and Klebsiella pneumoniae(10.0%,52/522).,The rates of imipenem resistance for E.coli,K.pneumoniae,Pseudomonas aeruginosa,and Acinetobacter baumannii were 6.4%,15.0%,27.8%,and 79.0%,respectively.All the Gram-positive pathogens were linezolid susceptible.Three vancomycin-resistant Enterococcus species were isolated.The overall 14-day mortality was 9.8%(95%confidence interval:7.2%-12.4%).A multivariate analysis showed that HM subtype severe aplastic anemia,A.baumannii,and malignancy non-remission were independent 14-day mortality risk factors.Conclusions:Gram-negative bacteria were the most common pathogens,with E.coli as the predominant strain,causing BSIs in HM patients.A carbapenem-resistant A.baumanni with a high mortality rate in HM patients made empirical antimicrobial choice a highly challenging issue.
基金supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No.2007BAC27B01)the Young Scientists Fund of the National Natural Science Foundation of China(No.21107121,21107122,20907059)
文摘The concentrations and geographical distribution of hexabromocyclododecane （HBCD） were investigated in 37 composite surface sediments from seven major river drainage basins in China, including Yangtze River, Yellow River, Pearl River, Liaohe River, Haihe River, Tarim River and Ertix River. The detection frequency of HBCD was 54%, with the concentrations ranged from below limit of detection （LOD） to 206 ng/g dry weight. In general, the geographical distribution showed increasing trends from the upper reaches to the lower reaches of the rivers and from North China to Southeast China. Compared to other regions in the world, the average concentration of HBCD in sediments from Yangtze River drainage basin was at relatively high level, whereas those from other six river drainage basins were at lower or similar level. The highest HBCD concentration in sediment from Yangtze River Delta and the highest detection frequency of t-IBCD in Pearl River drainage basins suggested that the industrial and urban activities could evidently affect the HBCD distribution. HBCD diastereoisomer profiles showed that y-HBCD dominated in most of the sediment samples, followed by ct- and [3-HBCD, which was consistent with those in the commercial HBCD mixtures. Further risk assessment reflected that the average inventories of HBCD were 18.3, 5.87, 3.92, 2.50, 1.77 ng/cm2 in sediments from Pearl River, Haihe River, Tarim River, Yellow River and Yangtze River, respectively.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB14010100)the "One-Three-Five" Strategic Planning program of the Chinese Academy of Sciences (No. YSW2013B01)the National Natural Science Foundation of China (Nos. 21321004, 21307148)
文摘Quartz particles are a toxic component of airborne paniculate matter（PM）.Quartz concentrations were analyzed by X-ray diffraction in eighty-seven airborne PM samples collected from three locations in Beijing before,during,and after the Asia-Pacific Economic Cooperation（APEC） Leaders＇ Meeting in 2014.The results showed that the mean concentrations of quartz in PM samples from the two urban sites were considerably higher than those from the rural site.The quartz concentrations in samples collected after the APEC meeting,when the pollution restriction lever was lifted,were higher than those in the samples collected before or during the APEC meeting.The quartz concentrations ranged from 0.97 to 13.2 μg/m^3,which were among the highest values amid those reported from other countries.The highest quartz concentration exceeded the Californian Office of Environmental Health Hazard Assessment reference exposure level and was close to the occupational threshold limit values for occupational settings.Moreover,a correlation analysis showed that quartz concentrations were positively correlated with concentrations of pollution parameters PM10,PM2.5,SO2 and NOx,but were negatively correlated with O3 concentration.The results suggest that the airborne quartz particles may potentially pose health risks to the general population of Beijing.
