OBJECTIVE: To establish a method of determination of difluorochloromethane in workplace air by direct sampling gas chromatography. METHODS: Difluorochloromethane in workplace air was collected with aluminum plastic composite film airbag and then directly injected. Difluorochloromethane was separated by DB-1 capillary column and detected with hydrogen flame ionization detector. RESULTS: Good linearity was obtained in the range of 1.50-15 042.90 mg/m~3 with the correlation coefficient of 0.999 96. The limit of detection was 1.26 mg/m~3 and the limit of quantitation was 3.78 mg/m~3. The minimum detection concentration was 1.26 mg/m~3 and the minimum quantification concentration was 3.78 mg/m~3. The standard recovery was 98.34%-99.19%. The within-run relative standard deviation(RSD) and the between-run RSD were 1.82%-3.72% and 2.17%-4.17%, respectively. The samples can be stored at room temperature for at least 7 days. CONCLUSION: This method is suitable for difluorochloromethane detection in workplace air.

Objective : To investigate the behavior problems and influencing factors of school-age students from the third to the sixth grade in Zhongshan,and to provide evidence for early intervention of behavior problems in children. Methods : According to the proportion of population in urban area and township in Zhongshan,students of Grade Three to Six from eight primary schools（three in urban area and five in township）were recruited by stratified sampling method. The behavior problems in children were assessed by the Conners Parent Symptom Questionnaire（PSQ）. Sociodemographic information,family discipline and so on was investigated by a general questionnaire. The influencing factors for behavior problems were analyzed by a logistic regression model. Results : A total of 2 292 questionnaires were issued,and 2 236 valid questionnaires were recycled,with an effective rate of 97.56%. The positive rate of behavioral problems was 11.72%. The results of multivariate logistic regression analysis showed that the risk factors for behavior problems were females（OR=1.594,95%CI：1.170-2.171）,birth asphyxia（OR=2.372,95%CI：1.320-4.261）,main family discipline（laissez-faire：OR=3.326,95%CI：1.450-7.630;doting：OR=3.244,95%CI：1.867-5.638;autocratic：OR=2.609,95%CI：1.584-4.296,mixed：OR=2.313,95%CI：1.669- 3.207）,less than four hours per week for father-child communication（OR=1.551,95%CI：1.052-2.286）,negative life events（OR=2.188,95%CI：1.448-3.308）,living in township（OR=2.031,95%CI：1.330-3.102）,academic performance （average：OR=2.786,95%CI：1.868-4.156;poor：OR=6.665,95%CI：3.236-13.727;very poor：OR=25.068,95%CI：5.786-108.617）;the protective factors were occupation of mother as civil servants or professional personnel（OR=0.449,95%CI：0.238-0.844）and higher grades（Grade Five：OR=0.496,95%CI：0.339-0.727;Grade Six：OR=0.468,95%CI：0.309-0.710）. Conclusion Females,birth asphyxia,main family discipline,less communication between father and child,occupation of mother,negative life events,place of residence,academic performance and grade were the influencing factors for behavior problems.

OBJECTIVE: To delineate cytogenetic and molecular abnormalities of a fetus carrying a de novo 46,X,der(X),t(X;Y)(p22.3;p11.2). METHODS: G-banded karyotyping and next-generation sequencing (NGS) were used to analyze the fetus, his father and sister. Single nucleotide polymorphism-based arrays (SNP-array), multiple PCR and fluorescence in situ hybridization (FISH) were utilized to verify the result. RESULTS: G-banded karyotyping at 320 bands showed that the fetus had a normal karyotype, while NGS has identified a 3.58 Mb microdeletion at Xp22.33 and a Y chromosomal segment of about 10 Mb at Yp11.32p11.2. With the sequencing results, high-resolution karyotyping at 550-750 bands level has determined the fetus to be 46,X,der(X)t(X;Y)(p22.3;p11.2). The result was confirmed by PCR amplification of the SRY gene, FISH and SNP-array assays. The karyotypes of his father and sister were both normal. His sister also showed no amplification of the SRY gene, and her NGS results were normal too, suggesting that the karyotype of the fetus was de novo. CONCLUSION Combined karyotyping, NGS, SNP-array, PCR and FISH assay can facilitate diagnosis of XX disorder of sex development.
Chromosomes, Human, X ; genetics ; Disorders of Sex Development ; genetics ; Female ; Fetus ; Humans ; In Situ Hybridization, Fluorescence ; Karyotyping ; Male ; Polymerase Chain Reaction ; Polymorphism, Single Nucleotide ; Translocation, Genetic

Objective To investigate the infection status, serotype distribution, drug sensitivity and molecular characteristics of diarrheagenic Escherichia coli (DEC) in patients with diarrhea in Guangdong Province. Methods Fecal samples were collected, cultured and isolated by traditional methods. Suspected Escherichia coli isolates were confirmed by multiplex PCR used for detecting specific virulence genes and bio-chemical methods. Positive strains were serotyped, characterized for drug sensitivity and analyzed by pulsed-field gel electrophoresis ( PFGE). Results The total positive rate of DEC in patients with diarrhea was 6.26%. The positive rates of enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), enterohemorrhagic Escherichia coli (EHEC), enteroadherent Escherichia coli (EAEC) and en-teroinvasive Escherichia coli (EIEC) were 2. 47% , 1. 54% , 1. 32% , 0. 62% and 0. 09% , respectively, with infections primarily in children aged 0-<7 years. The total seropositive rate was 52. 54% , with EHEC accounting for 15. 00% . DEC showed high sensitivity to imipenem, ciprofloxacin, ceftazidime and cefo-taxime. The multidrug resistance rate of DEC was 58. 45% , with EPEC being the most serious for multidrug resistance. PFGE results showed that ETEC, EHEC, EPEC and EAEC had a high degree of polymorphism. Conclusion EPEC is the predominant type of DEC circulating in Guangdong Province. Third-generation cephalosporins are the first drugs of choice for treating infections in children. Ciprofloxacin can be used to treat adults. The problem of multiple drug resistance of DEC is severe and efforts to monitor DEC infections and drug resistance should be strengthened.

Objective To analyze the serotype distribution and antibiotic resistance characteristics of Salmonella strains isolated in Guangdong province for better understanding the condition of Salmonella infection in patients with diarrhea.Methods Fecal samples collected from patients with diarrhea in Guangdong province were used to isolate Salmonella strains.Biochemical analysis was performed to identify these isolated strains.Serotyping and antimicrobial susceptibility testing were carried out for further analysis of the isolated Salmonella strains.Results The rate of Salmonella infection was 7.64％in 2015, and the male to female patient ratio was 1.52∶1.A total of 2 377 patients of all age groups were positive for Salmonella infection and the patients aged 0-6 years accounted for 81.74％.The isolation rate of Salmonella strains in the summer and autumn was higher than that in the winter and spring (10.73％ vs 4.24％;X2=463.77, P<0.01).The Salmonella isolation rates in different areas were as follows: 16.82％ in Zhuhai, 15.85％ in Heyuan, 11.81％ in Yangjiang, 10.68％ in Jiangmen, 8.49％ in Zhongshan, 8.07％ in Maoming, 8.05％ in Jieyang, 7.35％ in Shaoguan, 6.97％ in Foshan, 6.03％ in Dongguan, 5.48％ in Guangzhou and 0.00％ in Zhanjiang.And the differences between different regions were statistically significant (X2=367.67, P<0.01).The 2 377 isolated Salmonella strains were classified into 108 serotypes except for oneSalmonella strain that could not be classified.The top four predominant serotypes were 4,5,12:i:-, Salmonella enteritidis,Salmonella stanley and Salmonella typhimurium.Most Salmonella strains were sensitive to imipenem, azithromycin, ceftazidime, cefotaxime and trimethoprim/sulfamethoxazole, but multidrug resistance was common among those strains.Conclusion Salmonella serotypes of 4,5,12:i:-and Salmonella enteritidis are the predominant pathogens causing human Salmonella infections in Guangdong province.Ceftazidime and cefotaximeare are preferred in the treatment of Salmonella infections.Surveillance for drug resistance in Salmonella should be strengthened as multidrug resistant strains have become a serious problem in Guangdong province.

Objective To study the expression and function of miR-145 in papillary thyroid carcinoma (PTC).Methods PTC tissues and adjacent tissues were collected from 43 cases.Expression of miR-145 in PTC tissues and adjacent tissues was detected with RT-PCR.miR-145 analogue was used to transfect TPC-1cell to upregulate miR-145 expression.Brdu-ELISA method was used to detect the proliferation of TPC-1 cell.Flow cytometry instrument was used to detect the apoptosis and cell cycle of TPC-1 cell.Results RT-PCR test showed that relative expression of miR-145 in thyroid carcinoma tissue was 0.369±0.082,significantly lower than 1.029-±0.365 in tissue adjacent,and the difference was statistically significant (t=3.129,P=0.000).The expression of miR-145 in patients whose biggest tumor size ≥ 1 cm was lower than patients whose biggest tumor size ＜1 cm.Compared with patients with single tumor,the expression of miR-145 in patients with multiple tumor was lower,and the dif ferences were statistically significant (P＜0.05).miR-145 expression was enhanced by miR-145 analogue.Compared with negative control,the proliferative ability of thyroid cancer cell TPC-1 was suppressed significantly,and the difference was statistically significant (P＜0.05).In addition,up-regulation of miR-145 expression could block thyroid cancer TPC-1 in G2/M phase.The apoptosis rate of thyroid cancer cell TPC-1 increased significantly (P＜0.05).Conclusions miR-145 expression is decreased significantly in PTC tissue,and is associated with clinical pathological features.Up-regulation of miR-145 expression can inhibit thyroid cancer cell proliferation,block the cell cycle,and promote apoptosis,miR-145 may play an important role in occurrence and development of thyroid cancer.

Objective To investigate the expressions of homeobox gene 10 (HOXD10) and analyze its clinical significance. Methods Expressions of HOXD10 protein was detected by immunohistochemistry SP method in 53 cases of colorectal carcinoma tissues and corresponding normal tissues which was fixed by 4% formalin and embedded by paraffin.It was analyzed that the relationship between the expression of HOXD10 protein and clinico-pathological features. Results The positive staining rate of HOXD10 protein in normal colorectal mucosal tissue (5.7%)was significantly lower than that incolorectal carcinoma tissue(64.2%),the difference was statistically sig-nificant(P<0.05). In colorectal cancer tissue,the positive rate of HOXD10 protein in high differentiation(53.8%), T1+T2(38.5%),Ⅰ+Ⅱ(54.3%)and no lymph node metastasis(55.3%)was lower than that in low differentiation (73.0%),T3+T4(72.5%),Ⅲ+Ⅳ(83.3%)and lymph node metastasis,the difference was statistically significant (P < 0.05). However,it was not statistically significant between the positive rate of HOXD10 protein and the gender,age,primary site and tumor size in colorectal cancer patients(P>0.05). Conclusion The expression of HOXD10 protein is closely related to the invasion and metastasis of colorectal cancer.

Objective To prepare simulated stool specimens for proficiency testing ( PT) by mix-ing lentils with Salmonella, Shigella and Escherichia coli strains and to establish an assessment scheme for the detection of Salmonella and Shigella in clinical samples. Methods Salmonella, Shigella and Escherich-ia coli strains were respectively spiked to lentils in Cary-Blair transport medium to create simulated stool specimens. Various ratios of Escherichia coli to Salmonella strains were spiked to lentils to prepare mixed simulated stool specimens. The accuracy and stability of prepared stool samples for PT were tested in-house. Results of sample detection were collected from participating laboratories for further external quality assess-ment. Results The Escherichia coli and Salmonella strains mixed at ratios of 100 ∶ 1 to 106 ∶ 1 could be ef-ficiently isolated from the media. Enrichment was needed in order to effectively isolate Salmonella strains from the media when the ratios of Escherichia coli to Salmonella strains were 104 ∶ 1 to 106 ∶ 1. Of the16 participating laboratories, 14 laboratories (87. 5%) received a grade of“satisfactory” and the other 2 labo-ratories (12. 5%) received a grade of “mainly satisfactory”. Conclusion The simulated stool specimens and the PT procedures designed in this study were suitable for proficiency testing program on the detection of Salmonella, Shigella and other similar microbes.

Objective To evaluate the diagnostic value of endoscopic ultrasonography (EUS), and explore the efficacy of endoscopic treatment in patients with esophageal submucosal tumor. Methods Sixty-eight patients with esophageal submucosal tumor were selected, and the tumor was derived from the muscularis mucosa and submucosa according to the common endoscope and endoscopic ultrasonography detection. Endoscopic mucosal resection (EMR) was applied to remove submucosal tumor with diameter less than 1.0 cm, endoscopic piecemeal mucosal resection (EPMR) or endoscopic submucosal dissection (ESD) was applied to remove submucosal tumor with diameter 1.1 - 1.5 cm, and ESD was applied to remove submucosal tumor bigger than 1.5 cm. Samples were examined by pathology after treatment. Results Tumors in all the patients were completely removed, and the tumor diameter was 0.6-2.3 cm. Forty-one cases were treated with EMR, 9 cases were treated with EPMR and 18 cases were treated with ESD. Four patients had intra-operative bleeding that was stopped by electrocoagulation hemostasis. No perforation occurred in all cases. Postoperative pathology revealed 43 cases had leiomyoma, 23 cases had interstitialoma, and 2 cases had lipoma. Patients were reviewed by gastroscope 3 months after operation. The white scars formed in all patients, and there was no residue or recurrence. Conclusions Different origin layers and property of esophageal submucosal tumor can be diagnosed accurately by EUS, and endoscopic therapy (EMR, EPMR and ESD) is an effective treatment for submucosal tumor from muscularis mucosa and submucosa. Endoscopic therapy is safe and effective. It provides sufficient pathological information.

Objective To investigate the effect of the balloon Bionic midwifery on the delivery outcomes and to analyze the clinical value.Methods 1 683 parturients from June 2014 to May 2015 were selected.They were randomly divided into observation group (832 cases,applied balloon Bionic Midwifery) and control group 851 cases.We compared the labor,the postpartum hemorrhage,the outcomes of pregnancy and the rate of survival of neonates of the two groups.Results The first and second stage as well as the total stage of labors of the observation group were lower than the control group (P＜0.01);Also,the rate of cesarean delivery and the hemorrhage together with the asphyxia of neonates were lower than the control group (P＜0.01).However,the rate of vaginal delivery was higher than the control group (P ＜0.05).The differences between them had a great statistical significance.Conclusions The balloon bionic midwifery technology has an advantage in reducing the rate of cesarean delivery and the maternal pain of pregnant women as well as the maternal complications.It is an effective and safe midwifery technology.So it has a great value of spreading in clinical trials.