A hidden risk: Survival and resuscitation of Escherichia coli O157:H7 in the viable but nonculturable state after boiling or microwaving

We report the existence and resuscitation of viable but nonculturable (VBNC) Escherichia coli O157:H7 cells in drinking water induced by the common point-of-use disinfection treatments of boiling or microwaving. Tap water and saline samples containing E. coli O157:H7 culturable cells from a bovine isolate or two clinical isolates were boiled (1, 10, or 15 min) on a hot plate or microwaved (1.5 min) to reach boiling. No culturable E. coli O157:H7 cells were observed in the treated samples using conventional plating methods. In samples boiled for 1 or 10 min, two viability assays separately detected that 2-5.5% of the cells retained an intact membrane, while 28 to 87 cells out of the initial 10⁸ cells retained both measurable intracellular esterase activity and membrane integrity. In samples boiled for 15 min, no viable cells were detected. The microwaved samples contained 6-10% of cells with an intact membrane, while 21 to 108 cells out of the initial 10⁸ cells retained both membrane integrity and esterase activity. The number of viable cells retaining both metabolic activity and membrane integrity were consistent in all samples, supporting the survival of a small number of E. coli O157:H7 cells in the VBNC state after boiling for 1 or 10 min or microwaving. Furthermore, the VBNC E. coli O157:H7 cells regained growth at 37 °C in culture media containing autoinducers produced by common non-pathogenic E. coli, commonly present in the human intestine, and norepinephrine. The resuscitated cells were culturable on conventional plates and expressed mRNA encoding the E. coli O157 lipopolysaccharide gene (rfbE) and the H7 flagellin gene (fliC). This study highlights potential concerns for public health risk management of VBNC E. coli O157:H7 in drinking water disinfected by heat treatment at point-of-use. The public health significance of these concerns warrants further investigation.

Analysis of a registry database for esophageal cancer from high-volume centers in China

Esophageal cancer has a high incidence among malignancies in China, but a comprehensive picture of the status of its surgical management in China has hitherto not been available. A nationwide database has recently been established to address this issue.

METHOD

A National Database was setup through a network platform, and data was collected from 70 high-volume centers (>100 esophagectomies/per year) across China. Data was entered between January 2009 and December 2014, and was analyzed in June 2015 after a minimal follow-up of 6 months for all patients. 8181 patients with complete data who received surgery for primary esophageal cancer on the Database were included in the analysis.

RESULT

In this series, there were 6052 males and 2129 females, with a mean age of 60.5 years (range: 22-90 years). The pathology in 95.5% of patients was squamous cell carcinoma. The pathological stage distribution was 1.2% in stage 0, 2.5% in Ia, 11.5% in Ib, 14.8% in IIa, 36.1% in IIb, 19.3% in IIIa, 8.3% in IIIb, 6.2% in IIIc. 1800 patients (22.0%) with locally advanced disease received preoperative neoadjuvant therapy and 3592 patients (43.9%) underwent postoperative adjuvant chemotherapy and/or radiotherapy. The esophagectomies were performed through left thoracotomy approach in 5870 cases (72.6%), through right chest approach in 2215 cases (27.4%) including right thoracotomy (21.3%) and VATS (6.1%). The 30-day postoperative mortality rate was 0.6% (43 patients), and the overall postoperative complication rate was 11.6% (951 patients). The 1-, 3-, and 5-year overall survival rates were 82.6%, 61.6%, and 52.9%, respectively.

CONCLUSION

This National Registry Database from high-volume centers provides a comprehensive picture of surgical management for esophageal cancer in China for the first time. Squamous cell carcinoma predominates, but there is heterogeneity with respect to the surgical approach and perioperative oncologic management. Overall, surgical mortality and morbidity rates are low, and good survival rates have been achieved due to improvement of surgical treatment technology in recent years.

[Effect of pedicled thoracodorsal artery perforator flap on the repair of moderate to severe axillary scar contracture deformity]

Objective: To investigate the effect of pedicled thoracodorsal artery perforator (TDAP) flap on the repair of axillary moderate to severe scar contracture deformity. Methods: From January 2012 to January 2017, 29 patients with axillary moderate to severe scar contracture deformity were admitted to the the Second Xiangya Hospital of Central South University, including 18 females and 11 males, aged 14-42 years. There were 3 patients with cicatricial contracture deformity of bilateral axillas and 26 patients with cicatricial contracture deformity of unilateral axilla. After relevant preoperative examinations were completed and basic diseases were controlled, axillary scar was removed or released under the anesthesia of endotracheal intubation. The areas of wounds ranged from 7.5 cm×5.0 cm to 21.0 cm×8.5 cm after the operation. The pedicled TDAP flaps were used to repair the defects, which were thinned based on demand of the recipient sites before being transferred. The areas of flaps ranged from 9.0 cm×6.0 cm to 22.0 cm×10.0 cm. The donor sites were sutured directly. The status of thinned flaps, the survival of flaps after the operation and during follow-up, and the shoulder joint function during follow-up were observed. Results: Thirty-two pedicled TDAP flaps were harvested for repairing the defects. Among them, 14 flaps were transferred directly without thinning and the thickness of the flaps ranged from 9.0 mm to 15.0 mm, with average thickness of 13.6 mm.While the other 18 flaps were thinned, and the thickness of the thinned flaps ranged from 5.0 mm to 8.0 mm, with average thickness of 7.5 mm. The distal parts of 3 flaps in 3 patients showed small size of blackening or necrosis within 72 hours after the operation, and 2 of them were thinned and the other one was not. Finally, the 3 flaps were healed after hyperbaric oxygen therapy, dressing change, or other treatments. One flap occurred vein congestion 8 hours after the operation caused by pressure on the pedicle, and the color of the flap turned back to normal after the pressure was relieved. The rest of the flaps survived well. All the patients were followed up for 9 to 36 months, with an average of 18 months. All the flaps survived well, the color of the flaps was nearly the same as the recipient sites, and none of the flaps developed obvious contraction. The shoulder joint function of all patients was significantly improved compared with that before operation, with abduction angles of shoulder joints ranged from 90.0-145.0°, with an average of 130.0°. Conclusions: Pedicled TDAP flap is an relatively ideal choice for the repair of moderate to severe axillary scar contracture deformity, and better results will be achieved if the flaps are thinned to a appropriate thickness according to the condition of axillary defects.

[Cost-effectiveness of HIV self-testing strategy in men who have sex with men]

Objective: To analyze the cost-effectiveness and willingness-to-pay of HIV self-testing (HIVST) strategy and facility-based HIV rapid testing (HIV-RDT) strategy in men who have sex with men (MSM) in Zhuhai, and provide scientific evidence for making health policy. Methods: From the perspective of health service providers, the data of the costs and effectiveness of two HIV testing strategies in MSM in Zhuhai during January-September 2019 were collected, and a decision-tree model of cohort of 10 000 MSM was constructed by using software TreeAge Pro 2019 to measure the cost-effectiveness ratio (CER) and the incremental cost-effectiveness ratio (ICER). One-way and probability sensitivity analysis was performed for the uncertainty of the parameters in the model, and the cost-effectiveness and affordability curve was introduced to estimate the affordability of two strategies. Results: After the mobilization of MSM community-based organization through Internet and social media, 2 303 MSM had HIVST, in whom 33 were HIV positive (1.7%), and 816 MSM received HIV-RDT, in whom 35 were HIV positive (4.3%). The cost for per screening was 60.45 yuan and 240.43 yuan (RMB) respectively, and the cost for per positive screening was 4 218 yuan and 5 606 yuan (RMB) rerspectively. The results of the decision-tree model showed that the mean cost for a MSM using HIVST and using HIV-RDT was 44.67 yuan and 148.42 yuan (RMB) respectively, and the ICER was negative. HIVST strategy was a more cost-effective option when the willing-to-pay was below 6 528 yuan (RMB) for per positive screening, and HIV-RDT strategy was a more cost-effective option when the investment was higher than 6 528 yuan (RMB). Conclusion: HIVST strategy in Zhuhai is a public health project with economic value, and policy makers should strengthen the support to MSM community-based organization to promote the application of HIVST among MSM.

[Epidemiological characteristic and current status of surgical treatment for esophageal cancer by analysis of national registry database]

Objective: To investigate the epidemiological characteristics and current status of surgical management for esophageal cancer in China. Methods: A national database was setup through a network platform. The clinical data of esophageal cancer treated by surgery was collected from 70 major hospitals in China between January 2009 and December 2014. Results: Complete data of 8 181 cases of esophageal cancer patients who underwent surgery were recorded in the database and recruited in the analysis. Among them, 6 052 cases were male and 2 129 were female, the average age was 60.5 years.The epidemiological investigation results showed that 148 cases (1.8%) had history of psychological trauma, 7 527 cases (92.0%) were lower social economic status, 5 072 cases (62.0%) were short of fresh vegetables and fruits, 6 544 cases (80.0%) ate rough food frequently, 3 722 cases (45.5%) drank untreated water directly from lake or river or shallow well, 3 436 cases (42.0%) had a unhealthy eating habit, including habits of eating food fast (507 cases, 6.2%), eating hot food or drinking hot tea/soup (998 cases, 12.2%), eating fried food (1 939 cases, 23.7%), 4 410 cases (53.9%) had the habits of smoking cigarettes and 2 822 cases (34.5%) drank white wine frequently.The pathological results showed that 7 813 cases (95.5%) were squamous cell carcinoma, 267 cases were adenocarcinoma (3.3%), 25 cases were adenosquamous cell carcinoma (0.3%) and 50 cases were small cell carcinoma (0.6%). A total of 1 800 cases (22.0%) received preoperative neoadjuvant therapy due to locally advanced disease or difficulty of resection. The esophagectomies were performed through left thoracotomy approach in 5 870 cases (71.8%), through right chest approach in 2 215 cases (27.1%), and the remain 96 cases (1.2%) received surgery though other approaches.A total of 8 001 cases (97.8%) underwent radical resection, the other 180 cases (2.2%) received palliative resection. The 30-day postoperative mortality rate was 0.5%, the overall ≥ grade Ⅱ postoperative complication rate was 11.6% (951 cases). The 1-yr, 3-yr, and 5-yr overall actual survival rates were 82.6%, 61.6%, and 52.9%, respectively. Conclusions: The data analysis of the national database for esophageal cancer shows that bad eating habits or eating rough food without enough nutrients, lower social and economic status, drinking white wine and smoking cigarettes frequently may be correlated with tumorigenesis of esophageal cancer. However, strong evidences produced by prospective observation studies are needed. Overall, the long-term survival of esophageal cancer patients has been improved gradually due to the application of advanced surgical techniques and reasonable multimodality treatment.

Aptamer Binding Assay for the E Antigen of Hepatitis B Using Modified Aptamers with G-Quadruplex Structures

The e antigen of hepatitis B (HBeAg) is positively associated with an increased risk of developing liver cancer and cirrhosis in chronic hepatitis B (CHB) patients. Clinical monitoring of HBeAg provides guidance to the treatment of CHB and the assessment of disease progression. We describe here an affinity binding assay for HBeAg, which takes advantage of G-quadruplex aptamers for enhanced binding and stability. We demonstrate a strategy to improve the binding affinity of aptamers by modifying their sequences upon their G-quadruplex and secondary structures. On the basis of predicting a stable G-quadruplex and a secondary structure, we truncated 19 nucleotides (nt) from the primer regions of an 80-nt aptamer, and the resulting 61-nt aptamer enhanced binding affinity by 19 times (K_d = 1.2 nM). We mutated a second aptamer (40 nt) in one loop region and incorporated pyrrolo-deoxycytidine to replace deoxycytidine in another loop. The modified 40-nt aptamer, with a stable G-quadruplex and two modified loops, exhibited a 100 times higher binding affinity for HBeAg (K_d = 0.4 nM) than the unmodified original aptamer. Using the two newly modified aptamers, one serving as the capture and the other as the reporter, we have developed an improved sandwich binding assay for HBeAg. Analyses of HBeAg in serum samples (concentration ranging from 0.1 to 60 ng/mL) of 10 hepatitis B patients, showing consistent results with clinical tests, demonstrate a successful application of the aptamer modification strategy and the associated aptamer binding assay.

Cytotoxicity of Halogenated Tyrosyl Compounds, an Emerging Class of Disinfection Byproducts

Halogenated amino acids and peptides are an emerging class of disinfection byproducts (DBPs), having been detected in drinking water and in washed food products. However, the toxicological significance of these emerging DBPs remains unclear. In this study, the cytotoxicity of eight halogenated tyrosyl compounds was investigated in Chinese hamster ovary (CHO) cells using real-time cell analysis (RTCA). Dihalogenated tyrosyl compounds are more cytotoxic than their monohalogenated analogues. The cytotoxicity of the dihalogenated compounds is associated with their ability to induce intracellular reactive oxygen species (ROS), suggesting that oxidative stress is an important toxicity pathway of these compounds. Pearson correlation analysis of the cytotoxicity (IC₅₀ values) of these compounds with eight physicochemical parameters showed strong associations with their lipophilicity (logP) and reactivity (polarizability, E_LUMO). Finally, cytotoxicity testing of the concentrated extracts of a chloraminated mixture of eight dipeptides with bromide or iodide showed the cytotoxicity of these mixtures in the order: iodinated peptides > brominated peptides ≥ chlorinated peptides. These results demonstrate that halogenated peptide DBPs are toxicologically relevant, and further research is needed to understand the implications of long-term exposure for human health.

A Genome-Editing Nanomachine Constructed with a Clustered Regularly Interspaced Short Palindromic Repeats System and Activated by Near-Infrared Illumination

The RNA-guided CRISPR/Cas9 system is a powerful genome-editing technology with broad applications. Improving delivery efficiency and controllable activity of the CRISPR/Cas9 system is an area of intense research. We report the design, construction, and application of a CRISPR/Cas9 nanomachine (LACM), activated by a near-infrared (NIR) laser, which enables efficient delivery of single-guide RNA (sgRNA) into living cells and achieves controlled release of the sgRNA for the CRISPR/Cas9 activity. The LACM was constructed using a gold nanorod (AuNR) as a carrier that was decorated with dozens of protector DNAs stably hybridizing with the target binding domain of sgRNA. The DNA assembly on the AuNR protected the sgRNA. Irradiation with a NIR laser generated heat on the AuNR, resulting in controlled release of sgRNA, which guided the CRISPR/Cas9 genome editing. Successful editing of the EGFP and EMX1 genes in A549 and HEK293T cells, as well as knocking down of the PLK1 gene to induce apoptosis of the target cells, highlights the promising potential of the LACM for diverse applications.

[Correlation research between imaging performance and pulmonary function of pneumoconiosis patients at stage three]

Objective: To study the imaging performance and pulmonary function of pneumoconiosis patients at stage three. Methods: 89 cases of pneumoconiosis patients at stage three for high thousand volt back chest, chest CT, pulmonary function, analysis the relationship of high thousand volt back chest, chest CT manifestations and pulmonary function. Results: In patients with chest X-ray progressive massive fibrosis range of 2.31-102.95 cm(2), divide patients according to the X-ray performance into three groups, the difference of each group pulmonary function index FVC、FEV(1)、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV is statistically significant (P<0.01) , the difference of FEV(1)/FVC%、RV/TLC、DLCO is no statistical significance (P>0.05) . Checked by related, in pneumoconiosis patients at stage three, the X-ray manifestations and pulmonary function index FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV、DLCO showed a negative correlation (r=-0.326, -0.438, -0.251, -0.344, -0.317, -0.337, -0.425, -0.347, -0.230) . With the deterioration of the X-ray imaging findings, pulmonary function index FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV、DLCO is a trend of decrease (P<0.05) . The X-ray changes is not associated with RV/TLC. By linear regression analysis, FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV、DLCO regression equation are meaningful. The RV/TLC regression equations is meaningless. The volume of the patients with chest CT progressive massive fibrosis range of 4.86~179.74 cm(3), divide patients according to the chest CT performance into three groups, the difference of each group pulmonary function index FVC、FEV(1)、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV、RV/TLC is statistically (P<0.05) , the difference of FEV(1)/FVC%、DLCO is no statistical significance (P>0.05) . Checked by related, in pneumoconiosis patients at stage three, chest CT manifestations and pulmonary function index FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV showed a negative correlation (r=-0.360, -0.419, -0.256, -0.432, -0.366, -0.326, -0.254, -0.405, ) , It is not associated with the RV/TLC、DLCO. With the deterioration of the chest CT imaging findings, pulmonary function index FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV is a trend of decrease (P<0.05) . By linear regression analysis, FVC、FEV(1)、FEV(1)/FVC%、PEF、MEF(75%)、MEF(50%)、MEF(25%)、MVV regression equations are meaningful. The RV/TLC、DLCO regression equations are meaningless. Conclusion: It is correlated with chest X-ray, chest CT manifestations and pulmonary function in pneumoconiosis patients at stage three, that could help guide clinicians comprehensive evaluation in patients with pulmonary function status.

N-Nitrosamine formation from chloramination of two common ionic liquids

Ionic liquids (ILs) are a class of solvents increasingly used as "green chemicals." Widespread applications of ILs have led to concerns about their accidental entry to the environment. ILs have been assessed for some environmental impacts; however, little has been done to characterize their potential impacts on drinking water if ILs accidentally enter surface water. IL cations are often aromatic or alkyl quaternary amines that resemble structures of previously confirmed N-nitrosamine (NA) precursors. Therefore, this study has evaluated two common ILs, 1-ethyl-3-methylimidazolium bromide (EMImBr) and 1-ethyl-1-methylpyrrolidinium bromide (EMPyrBr), for their NA formation potential. Each IL species was reacted with pre-formed monochloramine under various laboratory conditions. The reaction mixtures were extracted using liquid-liquid extraction and analyzed for NAs using high performance liquid chromatography tandem mass spectrometry. At low concentration of IL (250 μmol/L), the yields of NAs (NMEA or NPyr) increased with increasing doses of monochloramine from both IL species. The total NA yield was as high as 2.5 ± 0.3 ng/mg from EMImBr, and as high as 8.6 ± 0.8 ng/mg from EMPyrBr. At high concentration of IL (5 mmol/L), the NA yield reached a maximum at 2.5 mmol/L NH₂Cl, and then decreased with subsequent increases in the reactant concentrations, demonstrating ILs' solvent effects. This study re-emphasizes the importance of preventing discharge of ILs to water bodies to prevent secondary impacts on drinking water.

[Iodine status of vulnerable populations in Henan Province of China three years after the implementation of new iodized salt standard]

Iodine nutrition surveillance of vulnerable population was conducted in 18 cities of Henan Province in 2015. The medians and quartiles of urinary iodine concentration in women of reproductive-age (n=3 318), pregnant women (n=36 366), lactating women (n=4 153), infants <2 years of age (n=1 017), and children aged 8-10 years (n=4 806) were 202.1(124.0, 310.0), 192.4(133.6, 262.4), 168.3(119.1, 248.3), 214.2(156.1, 272.3) and 90.0 (121.8, 285.6) μg/L, respectively. Iodine status of the vulnerable populations was generally regarded as adequate in Henan Province. But the median of urinary iodine concentration of reproductive-age women were slightly above the adequate level. The proportions above iodine adequate level were 26.7% in reproductive-age women, 29.4% in pregnant women and 22.5% in children aged 8-10 years.

Pesticides and trace elements in cannabis: Analytical and environmental challenges and opportunities

Cannabis is increasingly used for both medicinal and recreational purposes with an estimate of over 180 million users annually. Canada has recently legalized cannabis use in October 2018, joining several states in the United States of America (e.g., Colorado, California, and Oregon) and a few other countries. A variety of cannabis products including dry flowers, edibles, and oil products are widely consumed. With high demand for cannabis products worldwide, the quality of cannabis and its related products has become a major concern for consumer safety. Various guidelines have been set by different countries to ensure the quality, safety, and efficacy of cannabis products. In general, these guidelines require control of contaminants including pesticides, toxic elements, mycotoxins, and pathogens, as well as residual solvents in regard to cannabis oil. Accordingly, appropriate analytical methods are required to determine these contaminants in cannabis products for quality control. In this review, we focus on the current analytical challenges and method development for detection of pesticides and toxic elements in cannabis to meet various guidelines.

P6017Permanent left bundle branch area pacing for atrioventricular block: feasibility, safety and acute effect

Background

Left bundle branch area pacing (LBBAP), lacks adequate evaluation for AVB.

Purpose

We aimed to assess the feasibility, safety, and acute clinical outcomes of permanent LBBAP in patients with AVB.

Methods

We retrospectively recruited AVB patients with indication for ventricular pacing who had underwent LBBAP from May to Sep. 2018. ECG characteristics, pacing parameters, echocardiographic parameters and adverse events were evaluated during follow-up. Successful LBBAP was defined as the paced QRS morphology of RBBB pattern and QRSd less than 130ms.

Results

A total of 33 patients were involved in this study (mean age: 55.1±18.5 years; 66.7% male, 48.4% with bundle branch block,BBB). LBBAP was successfully performed in 90.9% (30/33) of all patients. The mean capture threshold of LBBAP was 0.76±0.26 V/0.4 ms during the procedure and 0.64±0.20 V/0.4ms at 3-month follow-up. The paced QRSd was 112.8±10.9 ms during the procedure and 116.8±10.4ms at 3-month follow-up. Baseline left or right BBB was corrected by LBBAP (153.3±27.8 ms vs. 122.2±9.9 ms) with a success rate of 68.7% (11/16). One ventricular septal lead perforation occurred soon after the procedure and LBBAP was successfully repeated by lead revision. Cardiac function and left ventricular synchronization at three-month follow-up presented slightly improvement as compared with baseline.

Table 1. Complications and changes in pacing parameters within 3 months after LBBAP Pacing parameters LBBAP (N=30) During the procedure Before discharge 3-month follow up Sensing amplitude, mV 14.4±5.1 15.8±11.7 14.6±4.6 Pacing threshold@0.4ms, V 0.76±0.26 0.59±0.16 0.64±0.20 Pacing impedance, Ω 691.7±133.8 588.0±79.3 554.7±93.7 Paced QRSd at 3.0V@0.4 ms output, ms 112.8±10.9 114.4±14.2 116.8±10.4 VP, % NA NA 79.4±24.6 Complications, n (%) 1 (3.3) 0 (0.0) 0 (0.0) Infection, n (%) 0 (0.0) 0 (0.0) 0 (0.0) Septal perforation, n (%) 1 (3.3) 0 (0.0) 0 (0.0) Dislodgement, n (%) 0 (0.0) 0 (0.0) 0 (0.0) QRSd, QRS duration; VP, ventricular pacing percentage.

Figure 1. Characteristics of LBBAP

Conclusion

Permanent LBBAP yielded stable threshold, narrow QRSd and preserved left ventricle synchrony with few complications. Our preliminary results indicate that LBBAP holds promise as an attractive physiological pacing strategy for AVB.

[Clinical analysis of scimitar syndrome in 6 pediatric patients]

Objective: To characterize the clinical features and outcomes of scimitar syndrome (SS) to aid the understanding of this syndrome. Methods: This retrospective study included 6 children who were diagnosed with SS at the pediatric cardiovascular center of Beijing Anzhen Hospital from January 2012 to September 2018. SS was diagnosed by echocardiography and confirmed by cardiac computed tomography angiography(CTA) or surgery. All data were collected to analyze the clinical and imaging characteristics and prognosis. Results: Among the 6 SS children (aged 2 months to 15 years; 5 males) weighed 5.6-17.1 kg. Three cases were infant type, the clinical manifestations were recurrent respiratory tract infection with growth retardation, including 2 cases with severe pulmonary hypertension, while 3 cases with adult type, were asymptomatic. Cardiac CTA imaging showed that the right single or all pulmonary veins descended through the diaphragm and converged into the inferior vena cava. One case was isolated infracardiac partial anomalous pulmonary venous connection (PAPVC) without other malformations. The remaining 5 cases complicated with atrial septal defect, different vascular and trachea malformations as well as spinal malformations. Vascular malformations included pulmonary veins stenosis, abnormal origin of pulmonary artery branches, collateral branches of systemic artery supplying local lung tissue, and persistent left superior vena cava. The treatment varied according to the specific location of anomalous pulmonary venous connection, the degree of pulmonary hypertension and the severity of clinical symptoms. Four cases underwent one-stage radical surgery, one case accepted intervention to occlude the collateral artery which was supplying the right lower lung and received stage Ⅱ radical surgery half a year later, and the remaining one case died from pulmonary hypertension crisis preoperation. Conclusions: Isolated SS can easily miss diagnosis due to mild clinical symptoms. Patients with complicated malformations can benefit from combination therapy. SS associated with severe pulmonary hypertension can lead to early death. Therefore, early diagnosis and appropriate treatment can improve the prognosis of patients.

[Clinical analysis of seven cases of H1N1 influenza-associated encephalopathy in children]

Objective: To investigate the clinical manifestations, diagnosis, and treatment of H1N1 influenza A-associated encephalopathy (IAE) in children. Methods: The clinical manifestations, laboratory tests, cranial magnetic resonance imaging (MRI), electroencephalography (EEG) examinations and treatments of seven children with H1N1 IAE hospitalized in Guangzhou Women and Children's Medical Center from December 2018 to January 2019 were retrospectively analyzed. Results: Five of the seven children with H1N1 IAE were female. The age at admission was 4 years and 5 months (range 7 months-9 years). Neurological symptoms occurred simultaneously or early (0-3 days) after the flu-like symptom appeared. The main clinical manifestations of neurological symptoms were seizures (repeated seizures in five cases and status convulsion in two cases, including one case of unexpected fever and repeated seizures in a nine-year old girl) accompanied with altered consciousness (drowsiness in five cases and coma in two cases). Cranial MRI in three cases displayed multifocal lesions, mainly in the bilateral thalamus, brainstem and cerebellar hemisphere. MRI also showed reversible splenial lesion in the corpus callusumin in three cases. EEG tracings were characterized by diffuse slow wave activity in four cases, and status epilepticus was monitored in one case. All the 7 cases were treated with oral oseltamivir. Three cases were treated with pulsed methylprednisolone and intravenous immunoglobulin. One case was treated with intravenous immunoglobulin alone and all the patients received oral oseltamivir. All the patients survived, with three patients had minor neurological sequelae at discharge. Conclusions: The main clinical manifestations of H1N1 IAE are seizures and altered consciousness. Cranial MRI combined with EEG is helpful for early diagnosis. Intravenous immunoglobulin and (or) methylprednisolone should be considered for severe cases.

Acute Toxicity and Hazardous Concentrations of Zinc to Native Freshwater Organisms Under Different pH Values in China

Zinc bioavailability to aquatic organisms varies greatly under different pH values. In the present study, five native species in China and four common international test species were selected to investigate the influence of changing pH on acute zinc toxicity. The results showed that the higher trophic levels exhibited increasing sensitivity to zinc as pH decreased. However, when the pH value was between 8 and 11, the acute toxicity of zinc was relatively constant. In addition, by using a species-sensitivity distribution (SSD) method, the short-term hazardous concentrations of zinc at different pH values (based on the 5th percentiles of the pH-specific SSDs) were determined to be 17.26 µg/L (pH 4), 48.31 µg/L (pH 5), 80.34 µg/L (pH 6) and 230.6 µg/L (pH 7), respectively. The present study provides useful information for deriving water quality criteria and assessing the risks of metals in the near future.

[BRAF gene mutations in ameloblastic fibromas]

OBJECTIVE

To investigate the BRAF gene mutations in ameloblastic fibroma (AF), and to further analyze the relationship between the BRAF mutation and clinical characteristics so as to provide new reference to the study of AF's molecular pathology.

METHODS

Sixteen cases diagnosed as AF at the Department of Oral Pathology, Peking University School of Stomatology between January 1990 and December 2017 were collected. Genomic DNA was extracted from formalin-fixed, paraffin embedded tissues using the QIAamp DNA Mini Kit (Qiagen, Germany) according to the manufacturer's instructions. Polymerase chain reaction (PCR) and direct sequencings were used to detect the BRAF gene mutations. The clinicopathological data, such as the age, location of the lesion, symptoms and treatments were retrospectively analyzed.

RESULTS

The sixteen cases of AF involved nine women and seven men aged 2-67 years. Three lesions occurred in the maxilla and thirteen in the mandible. The most common presenting symptom of AF was a painless slowly enlarging mass with swelling. Ten patients received conservative treatment and the other six patients received radical surgery. Three cases relapsed during the study period. BRAF gene mutation was found in sixteen of all the sixteen samples analyzed (100%). The BRAF mutation was a point mutation with a thymine-adenine transversion at nucleotide 1 799 of 15 exons, resulting in a change at residue 600 that substituted glutamine for valine. This mutation was the strongest activator of the downstream RAS/RAF/MEK/ERK-MAPK signaling pathway. This helped to bring about a gain-of-function mutation due to a V600E substitution. Many studies identified that BRAF regulated survival, apoptosis, and proliferation of cells by inducing MAPK pathways activation. For the existing cases, none of the age, sex, location, recurrence and treatments had a statistically significant correlation with BRAF mutation.

CONCLUSION

Our findings demonstrated high prevalence of BRAF V600E mutation in AF. The pathogenic role remains to be clarified．.

[The relationship between autoimmune thyroiditis and pregnancy outcomes of patients with PCOS following in vitro fertilization and embryo transfer IVF-ET]

Objective: To investigate the impact of autoimmune thyroiditis (AIT) on pregnancy outcomes in patients with polycystic ovary syndrome (PCOS) following the in vitro fertilization and embryo transfer (IVF-ET) by analyzing their pregnancy outcomes. Methods: The patients undergoing IVF-ET treatment diagnosed with PCOS in Peking University Third Hospital from May 2010 to December 2014 were investigated. According to the anti-thyroid antibodies (TPOAb or TGAb), patients were divided into AIT group and non-AIT group. The pregnancy outcomes of two groups were analysed for investigate the effect of AIT on pregnancy outcomes. Results: Four hundred and ninety patients with PCOS were enrolled, 119 (24.3%) of AIT group and 371 (75.7%) of non-AIT group. Patients with PCOS had a higher incidence (24.3%) of AIT. There was no correlation between AIT and the different pregnancy outcomes.TSH was negatively correlated with pregnancy as a risk factor. Hyperandrogenemia was negatively correlated with clinical pregnancy as a risk factor. Hyperprolactinemia was negatively correlated with delivery as a risk factor, while TSH was positively correlated with delivery. Conclusions: The incidence of AIT was higher in patients with PCOS. AIT was not the risk factor of adverse pregnancy outcomes for PCOS women undergoing IVF. The metabolic disorders (including hyperinsulinemia, hyperandrogenemia and hyperprolactinemia) were the risk factors of adverse pregnancy outcomes. Patients in AIT group had the high TSH level. They should be received more care and monitoring to make it conducive to delivery.

[Three-level logistic analysis related to influencing factors on condom use among female sex workers aged 35 years and above in Qingdao]

Objective: To analyze the influencing factors on condom use among 35-years-or-older female sex workers (OFSWs) in Qingdao by using the three-level logistic model. Methods: From March to June 2014, OFSWs were recruited in Qingdao, using respondent-driven sampling. Related information on OFSWs and their recent five sexual partners (not including husband) were obtained by conducting a questionnaire survey on OFSWs. A Three-level logistic regression model was conducted to analyze the influencing factors of condom use between OFSWs and their sexual partners. Results: A total of 420 OFSWs participated the survey as well as information on 2 100 sexual partners. Results from the empty model showed that the use of condoms among OFSWs having an aggregation that related to the levels of working sites and their own behaviors. Results from the three-levels of logistic model analysis showed that, OFSWs that having had junior middle school education (OR=1.450, 95%CI: 1.054-1.994)/high school education or above (OR=2.264, 95%CI: 1.215-4.222), knowing the function of condom use (OR=2.004, 95%CI: 1.273-3.154) would have higher rates of condom use. OFSWs with higher score of attitude on condom use (OR=0.796, 95%CI: 0.745-0.849), having had syphilis infections in the past (OR=0.657, 95%CI: 0.478-0.902) would have lower rate of condom use. For the sexual partners, the rate of condom use among OFSWs' regular partners were higher than that of OFSWs' boyfriends (OR=15.291, 95%CI: 8.441-27.700; OR=29.032, 95%CI: 15.413-54.682). Conclusion: Condom use of OFSWs was affected by behaviors of both OFSWs themselves and their sexual partners. Prevention and control programs should focus on OFSWs and their sexual partners at the same time. The key intervention contents should include target populations as: OFSWs with low level of education, having had infections of syphilis, those who do not use condoms with their trusted partners.

Formation, Identification, and Occurrence of New Bromo- and Mixed Halo-Tyrosyl Dipeptides in Chloraminated Water

Dipeptides are widely present in surface water and serve as precursors to form disinfection byproducts (DBPs) during disinfection (e.g., chloramination). Bromide (Br^-) and iodide (I^-) are common in many source waters, enhancing Br- and I-DBP formation. Recently Cl-, I-, and Cl-I-dipeptides were identified after chloramination of tyrosyl dipeptides in the presence of I^- and were detected in authentic disinfected drinking water samples. However, the formation and occurrence of Br- and mixed halogen (Cl, Br, and/or I)-dipeptides in disinfected water have not been studied. Here we investigated the formation of halogenated dipeptides from three aromatic dipeptides, phenylalanylglycine (Phe-Gly), tyrosylalanine (Tyr-Ala), and tyrosylglycine (Tyr-Gly), under chloramination in the presence of Br^- and I^- at environmentally relevant levels ([Br^-] and [I^-], 0 and 0 μg L^-1, 6 and 30 μg L^-1, 30 and 30 μg L^-1, 150 and 30 μg L^-1, 300 and 30 μg L^-1, and 900 and 30 μg L^-1, respectively). For the first time, N-Br- and N,N-di-Br- as well as N-Br- N-Cl- and N-Br-3-I-tyrosyl dipeptides were identified using infusion electrospray quadrupole time-of-flight mass spectrometry. Tyrosyl dipeptides produced N-Cl-, 3-I-/3,5-di-I-, and N-Cl-3-I-tyrosyl dipeptides, while Phe-Gly formed only N-Cl-/ N, N-di-Cl-Phe-Gly. To determine halogenated dipeptides in authentic water samples, we developed a new method of solid phase extraction and high-performance liquid chromatography with quadrupole ion trap mass spectrometry using reaction monitoring. 3,5-Di-I-Tyr-Ala and N-Br-Tyr-Ala were detected in treated water but not in the corresponding raw water, warranting further investigation into the occurrence of halogenated peptides in other drinking water systems.