Objective Since integrons play an important role in the spread of antibiotic resistance genes in bacteria,the characterization of a new resistance gene cassette in class 1 integron positive strains of E.coli was analyzed. Methods The presence and genetic content of class 1 integron were examined by PCR and sequencing.The sequence was analyzed by using some bioinformatics softwares.Results 5 class 1 integron positive strains were amplified by primers of in-F and in-B which were set for amplifying the region of antibiotics resistance genes.Among the 5 strains,an amplicon of 1009 bp was yielded.Sequencing analysis revealed that amplicon of 1009 bp harbored a 780 bp ORF.Further analysis with bioinformatics software showed that it was 99.6% and 99.5% identical to the known aadA23 and aadA21 cassette,and was just 66.4% identical to the known aadA5 cassette.It was conferring resistant to spectinomycin and streptomycin,and was given a new name aadA23b.Conclusions Multi-drug resistance genes has been proved changeable in E.coli clinical strains.The result not only stressed the need for continuing surveillance of antibiotic resistance in the molecular level,but also the need caring for genetic variation of drug resistance gene cassettes.

Objective To evaluate contrast-enhanced MRI sequence for diagnosing cholangiocarcinoma.Methods Cholangiocarcinoma was confirmed by surgery and pathology in 17 cases,all underwent preoperative CT and MRI T1-VIBE scan with contrast-enhancement sequence.We retrospectively analyzed imaging signs in two scan methods,including lesion position,number,size,enhancement degree,expansion degree of bile duct,invasion of adjacent artery and portal vein,and portal vein tumor thrombosis.The differences on detecting lesions between two methods were compared.Results The contrast to noise ratio (CNR) between tumor and liver tissue in MRI T1-VIBE images was obviously superior to that in CT images.Peripheral lesion boundary in T1-VIBE enhanced images was clearer than CT.One hemorrhage lesion was shown in T1-VIBE images,and tumor thrombosis was visible in the left branch of portal vein in 1 case.Bile duct wall lesions in T1-VIBE enhanced images was more evident than CT in hilar cholangiocarcinoma and extrahepatic cholangiocarcinoma.The VIBE enhanced images find more lesions in 9 out of 11 multiple focus cases,compared with CT images.Conclusions Contrast-enhanced MRI T1-VIBE sequence can give more comprehensive and clear evaluation on cholangiocarcinoma,and has important clinical diagnostic values.

Objective:To investigate the effect of dihydromyricetin (DMY) on LPS-induced septic shock in mice and the related underlying mechanism.Methods:The LPS-induced septic shock mice model was established after the mice were pre-treated by DMY for 7 days.The mortality rate was calculated at 24,48,72,96,120,144 and 168 h after the mice were intraperitoneal injected with LPS.For elucidation of underlying mechanism ,RAW246.7 were pre-incubated with DMY for 1 h,and then stimulated by LPS 100 ng/ml.Western blot was performed for determination of P-ERK,P-JNK and P-p38 expression.Immunohistochemistry was applied to explore c-Fos and c-Jun nucleus translocation.Results:DMY could significantly inhibit LPS-induced mice mortality.Inhibitory effect of DMY on the phosphorylation of JNK and p 38 contributed to the anti-inflammatory effect of DMY in vivo.Furthermore , DMY obviously prevented c-Fos and c-Jun nucleus translocation.Conclusion:The anti-inflammatory effect of DMY is attributed to the suppression on c-Fos and c-Jun nucleus translocation ,via inhibition of the phosphorylation of JNK and p 38.

Objective: To explore the impact of welding operations on the health status of workers with low working age, and provide a basis for occupational health risk assessment for workers of low working age. Methods: Used the method of cluster sampling to randomly selected workers from an automobile manufacturing plant in Guangzhou as research subjects: 982 workers with welding posts of 1 year ≤working age ≤5 years were welding groups, 707 workers with simple exposure noise of 1 year ≤working age ≤5 years were assembly groups, and 717 workers in pre-job medical examinations were pre-job groups from June 2017 to September 2018. Then conducted occupational health checks on all subjects, investigated and detected the occupational hazards in welding posts and assembly posts. Results: There was no statistical difference between the noise over-standard rate of welding posts' (59.3%, 16/27) and the assembly posts' (47.4%, 9/19) (P>0.05) . The over-standard rate of welding fume, manganese and its inorganic compounds in welding posts was 11.11% (3/27) . The results of occupational health examination showed that the detection rate of disease or abnormal of the welding group was 78.4% (770/982) higher than 70.2% (496/707) in the assembly group and 53.0% (380/717) in the pre-job group (the value of 2 were 14.92 and 122.37, respectively, P<0.05) . The rate of hearing loss of the assembly group and the welding group were 14.7% (104/707) and 19.3% (190/982) , respectively, which was higher than that of the pre-job group (10.5%, 75/717) , and the hearing loss rate gradually increased with the increase of working age (the value of linear-by-linear association were 12.04 and 44.67, respectively, P<0.01) . Compared with the hearing loss rate of each working age of the assembly group, the hearing loss rate of each working age of the welding group was higher, and when the working age was 3 years, the risk of hearing loss in the welding group was 2.70 times that of the assembly group (P<0.01) . The rate of pulmonary dysfunction in the welding group was 19.2% (189/982) higher than that in the pre-job group (12.6%, 90/717) , and it increased with the increase of working age (the value of linear-by-linear association was 15.97, P<0.01) . Conclusion Welding work seriously damages the health of workers with low working age, increases the hearing loss of workers and the occurrence of pulmonary dysfunction; manganese and its compounds increases noise-induced damage to the hearing system.

Objective: To investigate the value of MR unenhancement and dynamic enhancement scans for distinguishing non-hypervascular pancreatic neuroendocrine tumor (PNET) from pancreatic ductal adenocarcinoma (PDAC). Methods: Thirty five patients (45 lesions) with pathologically confirmed PNETs and 52 patients (53 lesions) with PDACs were retrospectively analyzed before surgery. All patients underwent MR unenhanced and dynamic enhanced scans (including arterial, venous and delayed phase). Based on arterial enhancement, PNETs were divided into hypervascular and non-hypervascular lesions. The morphologic characteristics (including location, size, quantity, margin and signal intensity) and enhancement patterns of non-hypervascular PNETs and PDACs were evaluated. Involvement of the pancreatic duct and bile duct, vascular invasion, peripancreatic infiltration and other organs metastasis were observed. Independent sample ttest was used to compare signal intensity ratio of nonhypervascular PNET and PDAC. Chi-square test was used to compare MRI characteristic and secondary signs. Results: PNET included 20 hypervascular and 25 nonhypervascular lesions. Enhancement degree of non-hypervascular PNET was higher than PDAC in the arterial, venous and delayed phase (P<0.01). Non-hypervascular PNET showed significantly higher frequencies (P<0.01) of venous hyper-or isoenhancement (20/25), delayed hyper-or isoenhancement (23/25) and a well-defined margin (17/25), but lower frequencies of ductal stricture and dilatation (P<0.01), pancreas atrophy (P<0.05), bile duct stricture (2/25), peripancreatic infiltration (8/25, P<0.01) and vascular invasion (8/25, P<0.05), when compared with PDAC. Conclusion A well-defined margin, hyper-or isoenhancement in the venous and delayed phase,and without ductal dilatation and pancreas atrophy are more common in non-hypervascular PNET, which may be distinguished from PDAC.