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Background N-nitrosodimethylamine (NDMA), a new disinfection by-product in drinking water, has attracted extensive attention due to its high detection rate and concentration. Objective To investigate the concentration of NDMA in drinking water in Nanjing situated in the lower Yangtze River Basin of China, and to evaluate associated human health risk. Methods In dry period (January–March) and wet period (July–September) of 2021, raw water, finished water, and tap water from 16 centralized water treatment plants in Nanjing were collected to detect the concentration of NDMA in water samples by solid phase extraction and gas chromatography-triple quadrupole mass spectrometry with programmable temperature vaporizer-based large volume injection. The concentrations of NDMA in water samples of different water types, water periods, and disinfection methods were analyzed, and the daily exposure levels and carcinogenic risk values of NDMA in drinking water of different exposure routes and different exposed populations were calculated. Monte Carlo simulation was implemented with Crystal Ball 11 software to establish a health risk assessment model and conduct sensitivity analysis. Results A total of 61 drinking water samples were collected in Nanjing, and NDMA was positive in all the water samples, with concentrations ranging from 1.36 to 25.65 ng·L−1 and an overall average concentration of (8.00±4.06) ng·L−1. There were no statistically significant differences in the average concentrations of NDMA among raw water, finished water, and tap water samples (F=2.875, P=0.064), between wet season and dry season (t=−0.855, P=0.397), or among different disinfection methods by liquid chlorine, sodium hypochlorite, and chlorine dioxide (F=0.977, P=0.385). The results of health risk assessment showed that the average carcinogenic risk of NDMA and its P95 were 5.95×10−6 and 1.12×10−5 respectively for oral intake of drinking water, and the values for dermal contact were both lower than 1.00×10−6. The mean carcinogenic risks of exposure to drinking water NDMA in children, adolescents, and adults were 1.84×10−6, 8.27×10−7, and 3.28×10−6, respectively. The results of sensitivity analysis showed that the contributions of daily drinking water volume and NDMA concentration in drinking water to the calculated health risk were high, and the contribution of body weight was negative. Conclusion There is a potential carcinogenic risk of NDMA in the drinking water of Nanjing section of the lower Yangtze River Basin，but it is within the acceptable range.
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Since the outbreak of COVID-19 in Wuhan, China, at the end of 2019, it has demonstrated China′s ability to identify unknown pathogens. At present, reports showed that the main transmission routes are respiratory droplets and indirect contact, other vertical transmission routes have yet to be confirmed. This review discusses the possible transmission routes of 2019-novel coronavirus (2019-nCoV), based on currently research, the main transmission routes are respiratory droplets and indirect contact, fecal-oral might bepossible, while aerosol, tear (conjunctival) and mother-to-fetus still have yet to be confirmed, providing a reference basis for 2019-nCoV prevention and control and public protection.
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Objective@#To investigate the clinical value of plasma EBV DNA in monitoring clinical efficacy in the treatment of nasopharyngeal carcinoma (NPC).@*Methods@#Clinical data of 799 patients initially diagnosed with NPC treated with radical intensity-modulated radiotherapy (IMRT) in our hospital from 2016 to 2017 were analyzed retrospectively. Prior to treatment, the correlation between plasma EBV DNA, clinical stage and tumor progression was analyzed. The relationship between EBV DNA and tumor progression was analyzed after radiotherapy and during follow-up.@*Results@#Before IMRT, the level of EBV DNA was positively correlated with both clinical stage and tumor progression (both P<0.001). At 6 to 8 weeks after IMRT, 19(2.3%) patients positive for plasma EBV DNA obtained the worst prognosis and 14 cases had tumor progression. At 6-8 weeks after IMRT, 9 patients were negative for EBV DNA and 3 cases had tumor progression. The tumor progression rate of patients with undetectable plasma EBV DNA at the end of IMRT was only 8.3%(64/772), and the progression-free survival rate significantly differed among three groups (all P<0.05). The sensitivity, specificity and accuracy rates of persistent positive plasma EBV DNA during follow-up were calculated as 77.6%, 100% and 98.1%, respectively.@*Conclusions@#The level of plasma EBV DNA in patients with NPC is correlated with tumor bearing and tumor progression prior to IMRT. At 6-8 weeks after IMRT, patients who are persistently positive for EBV DNA obtain the worst prognosis and should be given with appropriate adjuvant therapy. The correlation between persistent positive plasma EBV DNA during follow up and tumor progression yields a high accuracy rate, indicating that plasma EBV DNA is a reliable biomarker for monitoring the clinical efficacy after radical treatment for NPC patients.
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Objective To evaluate and compare the analytical performances and application values of three nucleic acid extraction methods for quantification of plasma Epstein-Barr Virus ( EBV ) DNA. Methods It used silica membrane spin column , boiling and automated magnetic bead method to extract viral nucleic acid in parallel , and combined real-time fluorescence quantitative PCR assays for quantitative EBV-DNA quantification.The performances of three methods were determined and compared by using the third-party reference materials , and the clinical values were analyzed by pairing detecting 100 NPC patients and 100 healthy subjects in pair .Results The accuracy and imprecision of three methods were all in line with requirements , and the results of clinical samples were linearly correlated . But actually the reproducibility and intermediate imprecision of the magnetic bead method were smaller and stable than those of the spin column method and the boiling method ( all <3％);the limit of detection for the magnetic bead method was 3.334 ×101 IU/ml, better than that of spin column method (4.159 ×101 IU/ml) and boiling method (8.511 ×101 IU/ml);the linear range of the magnetic bead method was 5.4 ×101 -5.4 ×105 IU/ml, slightly wider than that of the boiling method (5.4 ×102 -5.4 ×105 IU/ml); the ability of anti -Hb interference ability of magnetic bead method is better than that of boiling method ;and the positive rate and the mean viral load of the NPC samples measured with the magnetic bead method were significantly higher (95％, 8.342 ×103 IU/ml) than those measured with the spin column method (84％, 4.707 ×103 IU/ml) and the boiling method (78％, 2.571 ×103 IU/ml) ( P all<0.05).Conclusion The automated magnetic bead nucleic acid extraction method offered better analytical performance and higher clinical value for EBV DNA quantification in plasma .
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objective To investigate the epidemiological and molecular typing features of the pathogenic Haemophilus influenzae(H.influenzae)by biotyping,serotyping and pulsed-field gel electrophoresis(PFGE).Methods A total of 273 invasive isolates of H influenzae were collected from the pediatric patients with pneumonia at Chengdu Children Hospital of Sichuan province from 1988 and 2004 to 2007.The idenbfication of H.influenzae strains were done according to the laboratory standard methodology described by Manual of Clinical Microbiology(American).All strains were biotyped according to Kilian's classification with the API[R]NH system.And serotyped by a slide agglutination assay with type a to f specific antlaerum as described by Pittman.PCR method for identification of H.influenzae were performed as described by Falla.One hundred of 273 strains were analyzed by PFGE as described by Saito with some modifications.The resuIts of PFGE were analyzed by Bionumerics soft(Version 4.0,Applied Maths BVBA,Belium).Restilts 78.2%of 273 cases occurred under 1 years old.Eight biotypes were found among the 273 H.influenzae isolates.17.6%(48/273)of all isolates belonged to biotype Ⅰ,43.6%(119/273)were biotype Ⅱ,22.7%(62/273)were biotype Ⅲ,7.3%(20/273)were biotype Ⅳ,5.9%(16/273)were biotype Ⅴ,0.4%(1/273)were biotype Ⅵ,1.8%(5/273)were biotype Ⅶ and 0.7%(2/273)were biotype Ⅷ.respeetively.99.6% of all 273 isolates were nontypeable.There was only one isolate was serotvpe f Ninty-six PFGE genotypes were obtained in this study.One hundred strains demonstrated a variety of genomic Datterns by PFGE.The most isolates of the flame PFGE genotype(type 35)was 3 isolates.Each of93 PFGE genotypes was represented by only a single isolate.The genotypes distribution didn't correlate with the time distribution of the strains were isolated.Conclusion Nontypeable H.influenzae primarily caused acute Dneumoma in children under 1 years old.They mostly belonged to biotype Ⅰ,Ⅱ and Ⅲ biotypes.The nontypeable H.influenzae strains appeared to more heterogeneous patterns by PFGE genotyping.Genotyping may helP understand the molecular characteristics of outbreak and endemicity according to the results of PFGE.PFGE genotyping proved to have a much stronger discriminatory power than either serotyping or biotyping.Our findings suggest that PFGE analysis is useful for the epidemiologieal study of H.influenzae infections.
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Objective To discuss the diagnosis and management options of fetal nuchal cystic hygroma(NCH). Methods Ten cases of fetal nuchal cystic hygroma from Mar 1996 to Mar 2003 were retrospectively analyzed. The sonographic images, fetal karyotype examination after amniocentesis, TORCH results and pathology were reviewed. Results The sonogram detected a large cystic mass around the posterior of the neck. The smallest one was 5.3 cm?4.8 cm?4.0 cm in size and the biggest 12.6 cm?6.6 cm?4.0 cm. The nuchal ligament could be seen inside the mass. Four cases complicated with pleural effusions and 4 with pleural effusions, ascites and skin edema. One case was deliveried in full term and the other 9 cases were induced (including 4 fetal death). Seven cases were examined for TORCH of amniotic fluid among which only one TOX PCR positive. The karyotype examination was performed in 6 cases. The results were 45XO(3 cases), 45XO/46XX (60:40) and 45XX,-21,-22,+t(21;22). The only alive baby is 46XX. Conclusions Ultrasound and invasive amniocentesis to detect the fetal karyotype have an important role in early diagnosis and management of nuchal cystic hygroma. Nuchal cystic hygromas are associated with Turner’s syndrome and other chromosomal abnormalities.