Extensive Variation and Rapid Shift of the MG192 Sequence in Mycoplasma genitalium Strains from Patients with Chronic Infection

Mycoplasma genitalium causes persistent urogenital tract infection in humans. Antigenic variation of the protein encoded by the MG192 gene has been proposed as one of the mechanisms for persistence. The aims of this study were to determine MG192 sequence variation in patients with chronic M. genitalium infection and to analyze the sequence structural features of the MG192 gene and its encoded protein. Urogenital specimens were obtained from 13 patients who were followed for 10 days to 14 months. The variable region of the MG192 gene was PCR amplified, subcloned into plasmids, and sequenced. Sequence analysis of 220 plasmid clones yielded 97 unique MG192 variant sequences. MG192 sequence shift was identified between sequential specimens from all but one patient. Despite great variation of the MG192 gene among and within clinical specimens from different patients, MG192 sequences were more related within M. genitalium specimens from an individual patient than between patients. The MG192 variable region consisted of 11 discrete subvariable regions with different degrees of variability. Analysis of the two most variable regions (V4 and V6) in five sequential specimens from one patient showed that sequence changes increased over time and that most sequences were present at only one time point, suggesting immune selection. Topology analysis of the deduced MG192 protein predicted a surface-exposed membrane protein. Extensive variation of the MG192 sequence may not only change the antigenicity of the protein to allow immune evasion but also alter the mobility and adhesion ability of the organism to adapt to diverse host microenvironments, thus facilitating persistent infection.     

Host Inflammatory Response Inhibits Escherichia coli O157:H7 Adhesion to Gut Epithelium through Augmentation of Mucin Expression

Escherichia coli O157:H7, a major Shiga toxin-producing pathogen, has a low infectious dose and causes serious illness in humans. The gastrointestinal tract of cattle is the primary reservoir of E. coli O157:H7, and thus, it is critical to eliminate or reduce E. coli O157:H7 gut colonization. Given that E. coli O157:H7 produces effectors that attenuate inflammatory signaling, we hypothesized that the host inflammatory response acts to perturb E. coli O157:H7 intestinal colonization. Tumor necrosis factor alpha (TNF-α) treatment of HT-29 cells resulted in increased expression of inflammatory cytokine interleukin 1β (IL-1β), IL-8, and TNF-α genes and increased IL-8 protein and resulted in decreased adhesion of E. coli O157:H7. Similarly, E. coli O157:H7 adhesion to cattle colonic explants was reduced by TNF-α treatment. Irrespective of the presence of E. coli O157:H7, TNF-α enhanced activation of p65, the key mediator of NF-κB inflammatory signaling, whereas E. coli O157:H7 infection suppressed this pathway by inhibiting p65 activation in HT-29 cells. To further explore the mechanisms linking the inflammatory response to attenuated E. coli O157:H7 adhesion, mucin 2 (MUC2) expression was analyzed, considering that the intestinal mucus layer is the first defense against enteric pathogens and MUC2 is the major secretory mucin in the intestine. MUC2 expression in HT-29 cells was increased by TNF-α treatment and by E. coli O157:H7 infection. However, reducing mucin expression by blocking mitogen-activated protein kinase (MAPK) extracellular signal-regulated protein kinases 1/2 (ERK1/2) and/or phosphatidylinositol 3-kinase (PI3K)/Akt signaling increased E. coli O157:H7 adherence to HT-29 cells. These data suggest that the inflammatory cytokine response acts to protect host epithelial cells against E. coli O157:H7 colonization, at least in part, by promoting mucin production.     

The temporal course of the influence of anxiety on fairness considerations

This study investigated the potential causes of anxious people's social avoidance. The classic ultimatum game was utilized in concert with electroencephalogram recording. Participants were divided into two groups according to levels of trait anxiety as identified by a self‐report scale. The behavioral results indicate that high‐anxious participants were more prone to reject human‐proposed than computer‐proposed unequal offers compared to their low‐anxious counterparts. The event‐related potential results indicate that the high‐anxious group showed a larger feedback‐related negativity when receiving unequal monetary offers than equal ones, and a larger P3 when receiving human‐proposed offers than computer‐proposed ones, but these effects were absent in the low‐anxious group. We suggest anxious people's social avoidance results from hypersensitivity to unequal distributions during interpersonal interactions.     

Magnetically separable and reusable rGO/Fe3O4 nanocomposites for the selective liquid phase oxidation of cyclohexene to 1,2-cyclohexane diol

A series of magnetically separable rGO/Fe₃O₄ nanocomposites with various amounts of graphene oxide were successfully prepared by a simple ultrasonication assisted precipitation combined with a solvothermal method and their catalytic activity was evaluated for the selective liquid phase oxidation of cyclohexene using hydrogen peroxide as a green oxidant. The prepared materials were characterized using XRD, FTIR, FESEM, TEM, HRTEM, BET/BJH, XPS and VSM analysis. The presence of well crystallized Fe₃O₄ as the active iron species was seen in the crystal studies of the nanocomposites. The electron microscopy analysis indicated the fine surface dispersion of spherical Fe₃O₄ nanoparticles on the thin surface layers of partially-reduced graphene oxide (rGO) nanosheets. The decoration of Fe₃O₄ nanospheres on thin rGO layers was clearly observable in all of the nanocomposites. The XPS analysis was performed to evaluate the chemical states of the elements present in the samples. The surface area of the nanocomposites was increased significantly by increasing the amount of GO and the pore structures were effectively tuned by the amount of rGO in the nanocomposites. The magnetic saturation values of the nanocomposites were found to be sufficient for their efficient magnetic separation. The catalytic activity results show that the cyclohexene conversion reached 75.3% with a highest 1,2-cyclohexane diol selectivity of 81% over 5% rGO incorporated nanocomposite using H₂O₂ as the oxidant and acetonitrile as the solvent at 70 °C for 6 h. The reaction conditions were further optimized by changing the variables and a possible reaction mechanism was proposed. The enhanced catalytic activity of the nanocomposites for cyclohexene oxidation could be attributed to the fast accomplishment of the Fe²⁺/Fe³⁺ redox cycle in the composites due the sacrificial role of rGO and its synergistic effect with Fe₃O₄, originating from the conjugated network of π-electrons in its surface structure. The rapid and easy separation of the magnetic nanocomposites from the reaction mixture using an external magnet makes the present catalysts highly efficient for the reaction. Moreover, the catalyst retained its activity for five repeated runs without any drastic drop in the reactant conversion and product selectivity.

A series of magnetically-separable and reusable rGO/Fe₃O₄ nanocomposites were successfully synthesized for the selective liquid-phase oxidation of cyclohexene to 1,2-cyclohexane-diol.     

siRNA干扰沉默S100A4基因表达对喉癌Hep2细胞周期和侵袭的影响

目的应用RNA干扰技术下调喉癌Hep2细胞中S100A4基因的表达,探讨其对Hep2细胞周期和细胞侵袭力的影响。方法脂质体法转染S100A4siRNA至Hep2细胞。Real-time PCR和Western blot验证S100A4基因mRNA和蛋白水平的表达,流式细胞术和transwell实验分别检测下调S100A4表达对Hep2细胞周期和侵袭能力的影响。结果 S100A4 mRNA和蛋白表达水平明显降低,细胞增殖指数显著降低,并且处于G1期细胞数明显增多,细胞侵袭能力显著降低。结论 S100A4siRNA转染喉癌Hep2细胞能有效下调S100A4基因的表达,从而影响Hep2的细胞周期和抑制细胞的侵袭能力。     

广州地区早产儿先天性甲状腺功能低下症筛查结果分析

目的探讨早产儿与新生儿先天性甲状腺功能减低症（congenitalhypot hyroidism,CH）筛查各个阶段筛查结果的关系。方法选择2011年10月-2012年9月间进行新生儿筛查的干血片209860例,按照胎龄分为早产儿组、对照组1（足月儿组）、对照组2（过期产儿组）用免疫酶荧光法测定新生儿干血片促甲状腺素（thyroid stimulating hormone,TSH）值,筛查阳性患儿及时召回测定TSH、游离三碘甲状腺原氨酸（free triiodothyronine,FT3）、游离甲状腺素（free thyroxine,FT4）并作出诊断,并对早产儿组与对照组初筛阳性结果和确诊结果进行分析。结果早产儿组的初筛阳性率要低于足月儿组和过期产儿组,差别有统计学意义,早产儿组CH发病率要高于足月儿,差别有统计学意义,不同胎龄、出生体重早产儿的CH发病率存在线性相关,胎龄越小、出生体重越低,CH发病率越高。结论为了防止早产儿TsH延迟升高所带来的筛查假阴性,在新生儿筛查阶段对早产儿宜推迟采集测定足跟血TSH,加强围生期的保健和管理,减少早产儿的出生对于降低CH发病率,提高出生人口素质有着积极的意义。     

内镜下磁吻合术治疗先天性食管狭窄一例

采用传统手术方法治疗儿童先天性食管狭窄较困难且并发症多。本文报道1例利用磁吻合术实现儿童先天性食管狭窄微创治疗的临床经验。通过消化道内镜和胃造瘘方法将两个圆环状永磁体分别植入食管狭窄部位近、远端食管腔内,磁体对食管狭窄部位产生持续压榨作用以疏通食管。磁吻合术后1 d内磁环即完成良好对位,术后14 d胃造瘘口取出磁体,食管造影显示吻合口通畅情况良好,术后3个月复查食管造影通畅情况良好,随访6个月未发生任何并发症。     

Expression of miR-1304 in patients with esophageal carcinoma and risk factors for recurrence

BACKGROUND Esophageal carcinoma is a malignant gastrointestinal tumor with a very poor prognosis.MicroRNA(miR)-1304 is a newly discovered non-coding RNA,which shows differential expression in other cancers,and its clinical value in esophageal carcinoma remains unclear.AIM To explore the expression of miR-1304 in patients with esophageal carcinoma and its clinical value.METHODS The expression of miR-1304 in patients with esophageal carcinoma was analyzed based on the data on miR in esophageal carcinoma downloaded from The Cancer Genome Atlas database.Quantitative real-time polymerase chain reaction was adopted to determine the expression of miR-1304 in the tissues and serum of patients.The clinical diagnostic value of miR-1304 and independent factors for recurrence and prognosis of esophageal carcinoma were then analyzed.The potential target genes of miR-1304 were predicted,and then analyzed based on gene ontology,Kyoto Encyclopedia of Genes,and Genomes,and protein-protein interaction.RESULTS The expression of miR-1304 in the tissues and serum of patients with esophageal carcinoma increased,and was also increased according to the database.Patients with high expression of miR-1304 suffered increased rates of tumor≥3 cm,low differentiation and stage II+III.miR-1304 had a diagnostic value in identifying esophageal carcinoma,tumor size,differentiation and TNM stage.Tumor size,differentiation,TNM stage,and miR-1304 were independent risk factors for recurrence of esophageal carcinoma,and they had certain predictive and diagnostic value for the recurrence of esophageal carcinoma.Seventy-eight patients showed a 3-year survival rate of 38.46%,and patients with high expression of miR-1304 had a relatively lower survival rate.Multivariate analysis revealed that tumor size,differentiation,recurrence and miR-1304 were independent factors for the prognosis of patients.MiRTarBase,miRDB,and Targetscan predicted 20 target genes in total.Gene ontology enrichment analysis found 18 functions with aP<0.05,and Kyoto Encyclopedia of Genes,and Genomes analysis found 11 signal pathways with aP<0.05.String analysis of protein co-expression found 269 relationship pairs,of which co-expression with epidermal growth factor was the most common.CONCLUSION miR-1304 can be used as a potential indicator for the diagnosis and recurrence of esophageal carcinoma and for survival of patients with this disease.