Generation of double Holliday junction DNAs and their dissolution/resolution within a chromatin context.

Four-way DNA intermediates, also known as Holliday junctions (HJs), are formed during homologous recombination and DNA repair, and their resolution is necessary for proper chromosome segregation. To facilitate the biochemical analysis of HJ processing, we developed a method involving DNAzyme self-cleavage to generate 1.8-kb DNA molecules containing either single (sHJ) or double Holliday junctions (dHJs). We show that dHJ DNAs (referred to as HoJo DNAs) are dissolved by the human BLM­TopIIIα­RMI1­RMI2 complex to form two noncrossover products. However, structure-selective endonucleases (human GEN1 and SMX complex) resolve DNA containing single or double HJs to yield a mixture of crossover and noncrossover products. Finally, we demonstrate that chromatin inhibits the resolution of the double HJ by GEN or SMX while allowing BTRR-mediated dissolution.

Self-sacrificial tyrosine cleavage by an Fe:Mn oxygenase for the biosynthesis of para-aminobenzoate in Chlamydia trachomatis.

Chlamydia protein associating with death domains (CADD) is involved in the biosynthesis of para-aminobenzoate (pABA), an essential component of the folate cofactor that is required for the survival and proliferation of the human pathogen Chlamydia trachomatis. The pathway used by Chlamydiae for pABA synthesis differs from the canonical multi-enzyme pathway used by most bacteria that relies on chorismate as a metabolic precursor. Rather, recent work showed pABA formation by CADD derives from l-tyrosine. As a member of the emerging superfamily of heme oxygenase-like diiron oxidases (HDOs), CADD was proposed to use a diiron cofactor for catalysis. However, we report maximal pABA formation by CADD occurs upon the addition of both iron and manganese, which implicates a heterobimetallic Fe:Mn cluster is the catalytically active form. Isotopic labeling experiments and proteomics studies show that CADD generates pABA from a protein-derived tyrosine (Tyr27), a residue that is ∼14 Šfrom the dimetal site. We propose that this self-sacrificial reaction occurs through O2 activation by a probable Fe:Mn cluster through a radical relay mechanism that connects to the "substrate" Tyr, followed by amination and direct oxygen insertion. These results provide the molecular basis for pABA formation in C. trachomatis, which will inform the design of novel therapeutics.

Excision of a Protein-Derived Amine for p-Aminobenzoate Assembly by the Self-Sacrificial Heterobimetallic Protein CADD.

Chlamydia protein associating with death domains (CADD), the founding member of a recently discovered class of nonheme dimetal enzymes termed hemeoxygenase-like dimetaloxidases (HDOs), plays an indispensable role in pathogen survival. CADD orchestrates the biosynthesis of p-aminobenzoic acid (pABA) for integration into folate via the self-sacrificial excision of a protein-derived tyrosine (Tyr27) and several additional processing steps, the nature and timing of which have yet to be fully clarified. Nuclear magnetic resonance (NMR) and proteomics approaches reveal the source and probable timing of amine installation by a neighboring lysine (Lys152). Turnover studies using limiting O2 have identified a para-aminobenzaldehyde (pABCHO) metabolic intermediate that is formed on the path to pABA formation. The use of pABCHO and other probe substrates shows that the heterobimetallic Fe/Mn form of the enzyme is capable of oxygen insertion to generate the pABA-carboxylate.

MRI features and whole-lesion apparent diffusion coefficient histogram analysis of brain metastasis from non-small cell lung cancer for differentiating epidermal growth factor receptor mutation status.

AIM: To explore the utility of magnetic resonance imaging (MRI) characteristics and whole-lesion apparent diffusion coefficient histogram analysis of brain metastasis from non-small cell lung cancer (NSCLC) in the differentiation of epidermal growth factor receptor (EGFR) mutation status. MATERIALS AND METHODS: Forty-eight patients with brain metastases from NSCLC were enrolled in this retrospective study. Patients were subtyped into EGFR mutation (23 cases) and wild-type (25 cases) groups. Whole-lesion histogram metrics were derived from the apparent diffusion coefficient (ADC) maps, and imaging features were evaluated according to conventional MRI. Student's t-test or Mann-Whitney U-test, chi-squared test, and receiver operating characteristic (ROC) curve analysis were performed to discriminate the two groups and to determine the diagnostic efficacy of ADC histogram parameters. RESULTS: EGFR mutation group had more multiple brain metastases, less peritumoural brain oedema (PTBO), and lower peritumoural brain oedema index (PTBO-I) than EGFR wild-type group (all p<0.05). In addition, 90th and 75th percentiles of ADC and maximum ADC in the EGFR mutation group were significantly higher than in the EGFR wild-type group (all p<0.05). Ninetieth percentile of ADC had the highest area under the curve (AUC; 0.711), and it was found to outperform 75th percentile of ADC (AUC, 0.662; p=0.039) and maximum ADC (AUC, 0.681). CONCLUSIONS: Whole-lesion ADC histogram analysis and MRI features of brain metastasis from NSCLC are expected to be potential biomarkers to non-invasively differentiate the EGFR mutation status.

Dynamic interactions of lactic acid bacteria in Korean sourdough during back-slopping process.

AIMS: This study aimed to clarify the cause of quality reduction in Korean sourdough after successive back-slopping. METHODS AND RESULTS: We investigated the dynamic changes in lactic acid bacteria during the back-slopping process using genetic fingerprinting techniques. During the initial propagation phases, the dominant lactic acid bacteria were Fructilactobacillus sanfranciscensis (<5 log CFU per g sourdough), Latilactobacillus curvatus (9·5 log CFU per g sourdough) and Levilactobacillus brevis (6·5 log CFU per g sourdough). However, after the 11th propagation, F. sanfranciscensis became more prominent (>9·0 log CFU per g sourdough), whereas L. curvatus and L. brevis rapidly decreased. Monitoring these bacteria in the co-culture system revealed that acid-tolerant F. sanfranciscensis rapidly utilized maltose (1·65 g l-1  h-1 ) and produced large amounts of lactic acid, whereas L. brevis and L. curvatus consumed maltose slowly and L. curvatus was poorly tolerant to lactic acid. CONCLUSION: The results indicate that competition exists between the lactic acid bacteria in sourdough during the back-slopping process, and microbial succession by acid-tolerant species results in quality reduction of sourdough. SIGNIFICANCE AND IMPACT OF THE STUDY: This study uncovered the cause of microbial changes during the propagation of Korean sourdough and proposed a strategy to develop starters to produce high-quality bakery products.

[Clinical significance and management strategies of low-level viremia during the treatment of chronic hepatitis B].

Chronic hepatitis B and its related complications seriously endanger the lives and health of our country people. Although the first-line nucleos(t)ide analogs such as entecavir, tenofovir disoproxil fumarate and tenofovir alafenamide fumarate can inhibit virus replication to a certain extent, delay or prevent disease progression, and reduce the incidence of hepatitis B-related liver cancer, but in clinical practice, HBV DNA positivity is still detected continuously or intermittently in the serum of some patients. Therefore, low-level viremia has received widespread attention and triggered discussion, and has become the difficulties and hotspot of antiviral treatment of chronic hepatitis B. This article summarizes and discusses the definition and incidence in line with the main guidelines and studies, impact of disease control and clinical prognosis, and the current treatment options in order to provide definite reference for the management of low-level viremia during antiviral therapy in patients with chronic hepatitis B.

[Role of the liver-enriched transcription factor binding site mutation in the C promoter region of hepatitis B virus genome for HBx-enhanced hepatitis B virus replication].

Objective: To construct a recombinant HBV replication-type plasmid with liver-enriched transcription factor binding site mutation at proximal of HBV C promoter in order to elucidate the role of HBx-enhanced HBV replication. Methods: Site-directed mutagenesis technology was used to construct a recombinant plasmid with liver-enriched transcription factor binding site mutation at proximal of HBV C promoter on the basis of wild-type HBV replicating plasmid and HBV replicating plasmid lacking HBx expression. Subsequently, plasmid transfection was carried out in HBV liver cancer cell replication model and mouse replication model, and HBV replication intermediates of cells and mouse liver tissue were extracted for detection. Results: Based on the HBV replicating plasmid, the HBV replicating plasmid with liver-enriched transcription factor binding site mutation at proximal of HBV C promoter was successfully constructed. HBx-enhanced HBV replication were detected in both the HBV liver cancer replication model and the mouse replication model. After mutating liver-enriched transcription factor binding site mutation at proximal of HBV C promoter, the effect of HBx on the enhancement of HBV replication was not significantly affected. Conclusion: HBx may not enhance HBV replication through liver-enriched transcription factor binding site mutation at proximal of HBV C promoter. The role of other liver-enriched transcription factor binding sites in HBx-enhanced HBV replication needs further study.

Heterogeneous Chemistry of CaCO3 Aerosols with HNO3 and HCl.

Calcite (CaCO3) aerosols often serve as an idealized proxy for calcium-rich mineral dust. Their use has also previously been proposed for stratospheric solar radiation management (SSRM). Little is known about the heterogeneous chemistry of calcite aerosols with trace gases HNO3 and HCl and therefore their potential impact on stratospheric ozone (O3). Here we report the results of an experimental study of the uptake of HNO3 and HCl onto submicron CaCO3 particles in two different flow reactors. Products and reaction kinetics were observed by impacting aerosolized CaCO3 onto ZnSe windows, exposing them to the reagent gases at a wide range of concentrations, at 296 K and under dry conditions, and analyzing the particles before and after trace gas exposure using Fourier transform infrared spectroscopy (FTIR). A Ca(OH)(HCO3) termination layer was detected in the form of a HCO3- peak in the FTIR spectra, indicating a hydrated surface even under dry conditions. The results demonstrate the reaction of HNO3 with Ca(OH)(HCO3) to produce Ca(NO3)2, water, and CO2. HCl reacted with Ca(OH)(HCO3) to produce CaCl2 and also water and CO2. The depletion of the Ca(OH)(HCO3)/Ca(CO3) signal due to reaction with HNO3 or HCl followed pseudo-first-order kinetics. From the FTIR analysis, the reactive uptake coefficient for HNO3 was determined to be in the range of 0.013 ≤ γHNO3 ≤ 0.14, and that for HCl was 0.0011 ≤ γHCl ≤ 0.012 within the reported uncertainty. The reaction of HCl with airborne CaCO3 aerosols was also studied in an aerosol flow tube coupled with a quadrupole chemical ionization mass spectrometer (CIMS) under similar conditions to the FTIR study, and γHCl was determined to be 0.013 ± 0.001. Following previous modeling studies, these results suggest that the reactions of HCl and HNO3 with calcite in the stratosphere could ameliorate the potential for stratospheric solar radiation management to lead to stratospheric ozone depletion.

[Clinical study on the correlation between the duration of labor and postpartum hemorrhage].

Objective: To study the correlation between the duration of labor and postpartum hemorrhage. Methods: The delivery data of singleton first-term pregnant women who delivered vaginally at Beijing Obstetrics and Gynecology Hospital from January 1, 2017 to December 31, 2017 were collected, 3 104 cases met inclusion criteria. According to the duration of the first labor (t), they were divided into two groups: t≥8 hours was the observation group, t<8 hours was the control group. In order to ensure the baseline characteristics of the subjects in the two groups were balanced, propensity score matching (PSM) was adopted, with matching ratio 1∶1. Then the observation group was divided into four subgroups: group 8-12 h, group 12-16 h, group 16-20 h, group ≥20 h. According to the presence or absence of labor intervention (oxytocin use, artificial rupture of membranes, labor analgesia), the observation group and control group were divided into non-labor intervention observation group, non-labor intervention control group, labor intervention observation group, and labor intervention control group. The case data of 3 104 subjects were analyzed and the duration of labor and atonic postpartum hemorrhage rate of each subgroup were compared with the control group. Results: The duration of the second stage of labor and the first+second stages of labor in the observation group (median:0.8, 13.3 hours) and its subgroups were both longer than those in the control group (median:0.6, 5.1 hours), with statistically significant differences (all P<0.01). The rate of atonic postpartum hemorrhage in the observation group, group 16-20 h and group ≥20 h were higher than that in the control group [8.0%(124/1 552), 14.3%(41/287), 14.1%(12/85), 4.6%(72/1 552)], with significant statistical differences (all P<0.01). The duration of the second stage of labor and the first+second stages of labor in the observation group were both longer than those in the control group, regardless of the presence or absence of labor intervention, with statistically significant differences (all P<0.01). In both the observation group and the control group, the duration of the first stage of labor, the second stage of labor, and the first+second stages of labor with labor intervention were longer than those of the non-labor intervention, with significant statistical differences (all P<0.01). The rate of atonic postpartum hemorrhage in the observation group with labor intervention [8.7%(110/1 263)] was higher than that in the observation group without labor intervention [4.8%(14/289)], with a statistical difference (P<0.05). Conclusions: With the increase of the duration of the first stage of labor, the rate of atonic postpartum hemorrhage increases. The first stage of labor is closely related to the second stage of labor, and to a certain extent the duration of the second stage of labor increases with the length of the first stage of labor. With the increase of the duration of the first stage of labor, the rate of labor intervention and atonic postpartum hemorrhage also increase, which could serve as a clinical warning that excessive labor intervention may indicate a higher incidence of atonic postpartum hemorrhage.

[Observation of cosmetic effect of corneal interlamellar staining in patients with corneal leucoma].

Objective: To observe the clinical effect of corneal staining in patients with corneal leucoma. Methods: Restrospective case series study.Thirty eyes of 30 patients (17 males, 13 females) with corneal leucoma who underwent corneal interlamellar staining at Beijing Aier-Intech Eye Hospital from October 2014 to July 2018 were included. The mean age was 31.50±15.66 years. Postoperative follow-up was more than 1 year. All the patients underwent appearance examination, anterior segment examination with a slit lamp, B-scan examination and anterior segment OCT examination preoperatively and postoperatively. The effect of corneal staining, patient satisfaction and the incidence of complications were investigated. Results: The corneal epithelium of all the patients healed completely within 1-3 days after operation. The mean follow-up period was 30.68±18.02 months (range, 12.37-58.10 months). During the postoperative follow-up period, no staining permeation or inflammatory reaction in the anterior chamber occurred. The corneal color and appearance were well maintained in 18 patients (72.0%). Seven patients (28.0%) showed mild corneal color-fading. One patient was treated with enucleation and orbital hydroxyapatite implantation because of eye atrophy and corneal banding degeneration caused by the primary disease at 4 years after operation. The surgeon was satisfied with the improvement of the appearance of all cases; 22 patients (88.0%) were satisfied with the postoperative appearance. No significant complications were observed in all the cases. Conclusions: Corneal interlamellar staining is one of best choices for the treatment of corneal leucoma. It has advantages of quick postoperative recovery, long-standing color staining and good cosmetic effect. The operation is simple and easy to carry out and there is no obvious damage to eye tissues. (Chin J Ophthalmol, 2020, 56:465-472).

Identification of Peripheral Blood and Menstrual Blood Based on the Expression Level of MicroRNAs and Discriminant Analysis.

ABSTRACT: Objective To construct a discriminant analysis model based on the differential expression of multiple microRNAs （miRNAs） in two kinds of blood samples （peripheral blood and menstrual blood） and three non-blood samples （saliva, semen and vaginal secretion）, to form an identification solution for peripheral blood and menstrual blood. Methods Six kinds of miRNA （miR-451a, miR-144-3p, miR-144-5p, miR-214-3p, miR-203-3p and miR-205-5p） were selected from literature, the samples of five kinds of body fluids commonly seen in forensic practice （peripheral blood, menstrual blood, saliva, semen, vaginal secretion） were collected, then the samples were divided into training set and testing set and detected by SYBR Green real-time qPCR. A discriminant analysis model was set up based on the expression data of training set and the expression data of testing set was used to examine the accuracy of the model. Results A discriminant analysis statistical model that could distinguish blood samples from non-blood samples and distinguish peripheral blood samples from menstrual blood samples at the same time was successfully constructed. The identification accuracy of the model was over 99%. Conclusion This study provides a scientific and accurate identification strategy for forensic fluid identification of peripheral blood and menstrual blood samples and could be used in forensic practice.

Identification of Multiple Kinetic Populations of DNA-Binding Proteins in Live Cells.

Understanding how multiprotein complexes function in cells requires detailed quantitative understanding of their association and dissociation kinetics. Analysis of the heterogeneity of binding lifetimes enables the interrogation of the various intermediate states formed during the reaction. Single-molecule fluorescence imaging permits the measurement of reaction kinetics inside living organisms with minimal perturbation. However, poor photophysical properties of fluorescent probes limit the dynamic range and accuracy of measurements of off rates in live cells. Time-lapse single-molecule fluorescence imaging can partially overcome the limits of photobleaching; however, limitations of this technique remain uncharacterized. Here, we present a structured analysis of which timescales are most accessible using the time-lapse imaging approach and explore uncertainties in determining kinetic subpopulations. We demonstrate the effect of shot noise on the precision of the measurements as well as the resolution and dynamic range limits that are inherent to the method. Our work provides a convenient implementation to determine theoretical errors from measurements and to support interpretation of experimental data.

Nucleoid and cytoplasmic localization of small RNAs in Escherichia coli.

Bacterial small RNAs (sRNAs) regulate protein production by binding to mRNAs and altering their translation and degradation. sRNAs are smaller than most mRNAs but larger than many proteins. Therefore it is uncertain whether sRNAs can enter the nucleoid to target nascent mRNAs. Here, we investigate the intracellular localization of sRNAs transcribed from plasmids in Escherichia coli using RNA fluorescent in-situ hybridization. We found that sRNAs (GlmZ, OxyS, RyhB and SgrS) have equal preference for the nucleoid and cytoplasm, and no preferential localization at the cell membrane. We show using the gfp mRNA (encoding green fluorescent protein) that non-sRNAs can be engineered to have different proportions of nucleoid and cytoplasmic localization by altering their length and/or translation. The same localization as sRNAs was achieved by decreasing gfp mRNA length and translation, which suggests that sRNAs and other RNAs may enter the densely packed DNA of the nucleoid if they are sufficiently small. We also found that the Hfq protein, which binds sRNAs, minimally affects sRNA localization. Important implications of our findings for engineering synthetic circuits are: (i) sRNAs can potentially bind nascent mRNAs in the nucleoid, and (ii) localization patterns and distribution volumes of sRNAs can differ from some larger RNAs.

The Association Between Posttraumatic Negative Self-Conscious Cognitions and Emotions and Maladaptive Behaviors: Does Time Since Trauma Exposure Matter?

Negative beliefs about the self, self-blame, guilt, and shame have been consistently linked to emotional problems, such as posttraumatic stress disorder and depression, following trauma exposure. To expand understanding of the potential role of negative self-conscious cognitions and emotions in other forms of posttrauma maladjustments, such as maladaptive behaviors, the current study examined the associations between these cognitions and emotions with dissociation, alcohol use, and avoidant problem-solving. As a secondary goal, the influence of time since trauma exposure was considered given recent data suggesting that some posttraumatic responses require lengthier time following trauma to become salient. Multiple-group analysis was conducted in two groups of female survivors of intimate partner violence (IPV): women whose IPV experiences occurred within 3 months prior to assessment (early posttrauma phase [EPP]; n = 67) and those whose experiences occurred 12 months or more prior to assessment (chronic posttrauma phase [CPP]; n = 145). The results suggested model invariance. Posttraumatic negative self-conscious cognitions and emotions were significantly correlated with dissociation (EPP group: ß = .61, p < .001 and CPP group: ß = .48, p < .001), alcohol use (EPP group: ß = .31, p = .014 and CPP group: ß = .30, p < .001), and avoidant problem-solving (EPP group: ß = .58, p < .001 and CPP group: ß = .56, p < .001). The findings highlight the importance of negative self-conscious cognitions and emotions in posttrauma maladjustment and support intervening in these domains shortly after trauma exposure.

Spanish Abstracts by Asociación Chilena de Estrés Traumático (ACET) La asociación entre cogniciones y emociones negativas auto-conscientes postraumáticas y comportamientos maladaptativos: ¿Influye el Tiempo desde la Exposición al Trauma? COGNICIONES/EMOCIONES Y COMPORTAMIENTOS MALADAPTATIVOS Las creencias negativas acerca de sí mismo, la autoinculpación, la culpa y la vergüenza han sido consistentemente asociados a problemas emocionales, tales como el trastorno de estrés postraumático y la depresión, luego de la exposición a trauma. Para expandir la comprensión del rol potencial de las cogniciones y emociones negativas auto-conscientes en otras formas de inadaptación post-trauma, como comportamientos maladaptativos, el presente estudio examinó las asociaciones entre esas cogniciones y emociones con disociación, uso de alcohol, y estilo evitativo de resolución de problemas. Como un objetivo secundario, se consideró la influencia del tiempo desde la exposición al trauma dados los datos recientes que sugieren que algunas respuestas post-traumáticas requieren un mayor tiempo luego del trauma para hacerse salientes. Se realizó un análisis de grupos múltiples en dos grupos de mujeres sobrevivientes de violencia de pareja (IPV, por su sigla en inglés); aquellas cuyas experiencias de IPV ocurrieron en los últimos 3 meses (fase temprana post-trauma [FTP]; n = 67) y aquellas cuyas experiencias ocurrieron hace 12 meses o más (fase crónica post-trauma [FCP]; n = 145). Los resultados sugirieron invariancia del modelo. Las cogniciones y emociones negativas auto-conscientes se correlacionaron significativamente con disociación (grupo EPP: ß = .61, p < .001 y grupo CPP: ß = .48, p < .001), uso de alcohol (grupo EPP: ß = .31, p = .014 y grupo CPP: ß = .30, p < .001), y estilo evitativo de resolución de problemas (grupo EPP: ß = .58, p < .001 y grupo CPP: ß = .56, p < .001). Los hallazgos destacan la importancia de las emociones y cogniciones negativas auto-conscientes en la inadaptación postrauma y apoyan la intervención en esos dominios prontamente luego de la exposición a trauma.

Plasmid curing resulted in improved heterologous gene expression in Leuconostoc citreum EFEL2700.

Leuconostoc citreum EFEL2700 isolated from kimchi was used as a host strain for genetic and metabolic engineering in our previous studies, but the cells of EFEL2700 contained a cryptic plasmid (P-cells). Thus, we created plasmid-free cells (F-cells) using the CRISPR/Cas9 system. In this study, we compared the microbial characteristics of P- and F-cells in terms of growth rate, biochemical properties, transformation efficiency, plasmid copy number and protein expression level. When the growth rate was measured in MRS medium at 30°C, no significant difference (P > 0·01) was observed. Biochemical properties, tested using an API 50CHL kit, showed no differences. Transformation efficiency of F-cells, measured using pCB4270, was higher (1·3 × 104 CFU per µg DNA) than that of P-cells (5·0 × 103 CFU per µg DNA). Copy number after transformation of pCBBgl was 4-fold higher for F-cells than for P-cells. When ß-glucosidase activity was assayed in the above experiment, F-cells showed 3·4-fold higher values than P-cells. In conclusion, this study demonstrates that plasmid curing in L. citreum EFEL2700 improves its characteristics as a gene expression host. SIGNIFICANCE AND IMPACT OF THE STUDY: Leuconostoc citreum EFEL2700 (P-cell) isolated from kimchi is a useful food-grade host for expressing heterologous genes. The presence of a cryptic plasmid is thought to limit efficient gene expression. In this study, we compared the microbial and genetic changes after plasmid curing in this strain. The plasmid-free strain showed improved levels of transformation efficiency, copy number and heterologous gene expression without alterations in phenotypes such as the growth rates and biochemical properties. The resulting strain of L. citreum EFEL2701 (F-cell) can be used as an efficient host for genetic engineering.

Does a history of childhood abuse moderate the association between symptoms of posttraumatic stress disorder and borderline personality disorder in survivors of intimate partner violence?

OBJECTIVE: This study examined whether a history of childhood abuse (CA) strengthened the association between borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD) in the aftermath of intimate partner violence (IPV). This hypothesis arises from clinical literature but has not been examined empirically. We predicted that a history of CA would enhance associations between BPD features and PTSD symptoms. METHOD: Dimensional assessment of both PTSD and BPD was made in a sample of 211 women who sought mental health services following IPV. Two analyses were conducted using clinician-assessed DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th ed.) PTSD symptoms: (a) total score and (b) symptom clusters. RESULTS: Using path analysis, results indicated significant associations between BPD features and PTSD symptoms, but no significant interaction between BPD and CA in either analysis. CONCLUSIONS: Results are discussed given current understanding of comorbidities involving PTSD, with particular attention to potential implications for clinical practice. Areas for future research are proposed.

[Predictive value of cervical length measured by transvaginal ultrasound during the second and the third trimester of pregnancy for preterm birth in twin pregnancies].

Objective: To investigate the predictive value of cervical length (CL) measured by transvaginal ultrasound for preterm birth <32 weeks, <34 weeks in twin pregnancies in the second and the third trimester of pregnancy. Methods: A total of 490 twin pregnant women with CL measured by transvaginal ultrasound during the second trimester of pregnancy (20-24 weeks) and the third trimester of pregnancy (28-32 weeks) delivered in Peking University Third Hospital, and Tongzhou Maternal and Child Health Hospital from January 2014 to December 2017 were collected, and 161 cases out of which were measured by CL during both the second trimester and the third trimester of pregnancy. Based on the measured gestational weeks, 427 cases were in the second trimester group and 224 cases in the third trimester group. The predictive value of CL for preterm birth was evaluated by calculating the optimal cut-off point with sensitivity and specificity. Logistic regression analysis was used to assess the relationship between CL and preterm birth after adjusting for confounding factors (age of pregnant women, chorionic status, mulipara, assisted reproductive pregnancy and pre-pregnancy body mass index). Results: (1) The median CL of pregnant women in the second trimester group and the third trimester group were 36 mm (33-40 mm) and 28 mm (18-33 mm) respectively. In the second trimester group, 151 cases (35.4%, 151/427) were preterm birth and 276 cases (64.6%, 276/427) were full-term birth; the median CL of preterm and full-term pregnant women were 34 mm (30-37 mm) and 37 mm (34-40 mm), respectively, with significant difference (P<0.01). In the third trimester group, 100 cases (44.6%, 100/224) were preterm birth and 124 cases (55.4%, 124/224) were full-term birth; the median CL of preterm and full-term pregnant women were 22 mm (15-30 mm) and 31 mm (23-34 mm), respectively, with significant difference (P<0.01). (2) Prediction of preterm birth <32 weeks and <34 weeks was performed with CL in the second trimester group. The area under the receiver-operating characteristics curve were 0.78 (95%CI: 0.70-0.86) and 0.71 (95%CI: 0.64-0.79), respectively. The optimal cut-off points were 36.5 mm and 33.5 mm, respectively. After adjusting for confounding factors, CL was inversely associated with preterm birth <32 weeks and <34 weeks of gestation. (3) Prediction of preterm birth <32 weeks and <34 weeks were performed with CL in the third trimester group. The area under the receiver-operating characteristics curve were 0.86 (0.75-0.96) and 0.75 (0.67-0.84), respectively. The optimal cut-off points were 17.5 mm and 18.5 mm, respectively. After adjusting for confounding factors, CL was inversely associated with preterm birth at <32 weeks and <34 weeks of gestation. Conclusions: CL measured by transvaginal ultrasound in the second and the third trimester is a good predictor for preterm birth of twin pregnancy. CL≤36.5 mm and ≤33.5 mm at 20-24 weeks of gestation could predict preterm birth <32 weeks and <34 weeks respectively. CL≤17.5 mm and ≤18.5 mm at 28-32 weeks of gestation could predict preterm birth <32 weeks and <34 weeks respectively.

Src-type tyrosine kinase p56lck is critical for thymic stromal lymphopoietin-induced allergic rhinitis.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a regulator of mast cell-mediated allergic inflammatory reactions, but the manner in which TSLP contributes to allergic rhinitis (AR) remains unclear. OBJECTIVE: Here, we sought to determine that TSLP plays a crucial role in AR by interacting with Src-type tyrosine kinase p56lck and STAT6 and promoting mast cells degranulation. METHODS: The effects of TSLP on mast cell degranulation and AR were analysed in human mast cell line (HMC-1 cells), ovalbumin (OVA)-induced AR animal model, and human subjects. Small interfering RNA experiments were performed in HMC-1 cells and OVA-induced AR model. Immune responses were analysed by enzyme-linked immunosorbent assay, Western blotting, immunoprecipitation, and histological studies. RESULTS: Thymic stromal lymphopoietin levels and mast cell-derived p56lck activation were elevated in human subjects with AR, and in AR mice, exogenous TSLP accelerated TH2-allergic inflammatory reactions by up-regulating p56lck and STAT6. On the other hand, depletion of TSLP, p56lck, and STAT6 ameliorated clinical symptoms in AR mice. The selective inhibitor of p56lck, damnacanthal, inhibits AR reactions. CONCLUSION: Collectively, these observations suggest a role for TSLP/p56lck/STAT6 in AR and offer insight into potential therapeutic strategies.

Early development of de novo hepatocellular carcinoma after direct-acting agent therapy: Comparison with pegylated interferon-based therapy in chronic hepatitis C patients.

Patients with chronic hepatitis C who achieve a sustained viral response after pegylated interferon therapy have a reduced risk of hepatocellular carcinoma, but the risk after treatment with direct-acting antivirals is unclear. We compared the rates of early development of hepatocellular carcinoma after direct-acting antivirals and after pegylated interferon therapy. We retrospectively analysed 785 patients with chronic hepatitis C who had no history of hepatocellular carcinoma (211 treated with pegylated interferon, 574 with direct-acting antivirals) and were followed up for at least 24 weeks after antiviral treatment. De novo hepatocellular carcinoma developed in 6 of 574 patients receiving direct-acting antivirals and in 1 of 211 patients receiving pegylated interferon. The cumulative incidence of early hepatocellular carcinoma development did not differ between the treatment groups either for the whole cohort (1.05% vs 0.47%, P = .298) or for those patients with Child-Pugh Class A cirrhosis (3.73% vs 2.94%, P = .827). Multivariate analysis indicated that alpha-fetoprotein level >9.5 ng/mL at the time of end-of-treatment response was the only independent risk factor for early development of hepatocellular carcinoma in all patients (P < .0001, hazard ratio 176.174, 95% confidence interval 10.768-2882.473) and in patients treated with direct-acting agents (P < .0001, hazard ratio 128.402, 95% confidence interval 8.417-1958.680). In conclusion, the rate of early development of hepatocellular carcinoma did not differ between patients treated with pegylated interferon and those treated with direct-acting antivirals and was associated with the serum alpha-fetoprotein level at the time of end-of-treatment response.

Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review.

Both isobaric and hyperbaric bupivacaine have been used for spinal anaesthesia for elective caesarean section, but it is not clear if one is better than the other. The primary objective of this systematic review was to determine the effectiveness and safety of hyperbaric bupivacaine compared with isobaric bupivacaine administered during spinal anaesthesia for elective caesarean section. We included 10 studies with 614 subjects in the analysis. There was no evidence of differences either in the risk of conversion to general anaesthesia, with a relative risk (95%CI) of 0.33 (0.09-1.17) (very low quality of evidence), or in the need for supplemental analgesia, the relative risk (95%CI) being 0.61 (0.26-1.41) (very low quality of evidence). There was also no evidence of a difference in the use of ephedrine, the amount of ephedrine used, nausea and vomiting, or headache. Hyperbaric bupivacaine took less time to reach a sensory block height of T4, with a mean difference (95%CI) of -1.06 min (-1.80 to -0.31). Due to the rarity of some outcomes, dose variability, use of adjuvant drugs and spinal technique used, future clinical trials should look into using adequate sample size to investigate the primary outcome of the need for supplemental analgesia.