风险态度对农户家庭信贷资金可得性水平的影响效应研究

本文基于中国家庭追踪调查实证微观数据,运用有序Probit实证估计了风险态度对农户家庭信贷资金可得性水平的影响效果。实证研究发现:厌恶型的风险态度在5%显著性水平上对农户家庭信贷资金可得性水平有明显的促进效应,且运用PSM模型的半径匹配估计法对估计结果进行了实证检验,检验结果表明有序Probit模型的估计结果稳健可靠,由此表明厌恶型的风险态度有利于增强农户金融信贷资金可得性水平。同时地区异质性分析发现西部地区风险态度对信贷资金可得性水平的影响效果较小且统计水平上不显著,据此表明西部地区厌恶型的风险态度对农户家庭信贷资金可得性水平的影响效果微弱且统计上不显著。

服务外包如何推动制造业价值链位置提升——基于跨国和中国样本的系统性检验

在实现产业价值链升级的政策目标及服务外包已成为全球制造业发展重要趋势的现实背景下,探讨服务外包如何促进我国制造业实现价值链位置攀升具有重要意义。本文基于1995—2018年最新的区域间投入产出表(OECD-ICIO),系统考察离岸和在岸服务外包对一国制造业价值链位置提升的影响效应及机制,并进一步选取中国样本进行比较分析。研究发现:(1)服务外包有利于一国制造业在产业链上所处相对环节向下游移动,且离岸服务外包在推动全球价值链嵌入位置提升中发挥更重要的作用。(2)机制分析来看,服务外包通过替代货物中间品进口、减少中间品跨境购买数量以及提高生产率尤其是劳动生产率三类渠道,推动一国价值链环节向下游移动,还通过总部经济和吸收能力大大加强了在岸服务外包对价值链嵌入位置的影响程度。(3)异质性分析表明,服务外包对制造业嵌入位置变动的影响随时间推移和收入水平降低而逐渐弱化,且对于不同技术行业和服务类型具有差异影响。(4)进一步采用中国样本拓展分析发现,结果与跨国数据总体一致,中国制造业发展离岸外包与在岸外包同样会降低制造业行业上游度,进而推动全球价值链嵌入位置提升,并且离岸外包相对在岸外包效应更大。本研究在发展贸易新业态新模式下能够为我国借助大力发展服务外包产业促进制造业价值链升级等方面提供理论和经验借鉴。

黑龙江东部大豆疫霉生理小种及毒性结构时空动态分析

为了研究大豆疫霉生理小种和致病型随时间和空间而变化的规律,连续4 a从黑龙江省东部地区发病较严重的4个代表性地块采集土壤样品,采用叶碟诱捕法分离出其中的大豆疫霉,将确认为大豆疫霉的菌株利用下胚轴伤口接种法鉴定其生理小种和致病型,对于科学使用大豆品种具有重要意义。结果表明,497株大豆疫霉属于135种致病型,包含29个生理小种,1株IRT和105个新致病型,其中16,18,22,28,35号生理小种为中国首次报道,而4,33,38,39,43,48,49号生理小种未分离到。13号小种分离频率最高,为3.2%,1号小种分离频率仅为2.4%。结果显示,黑龙江东部大豆疫霉群体致病力偏弱,对8个Rps基因致病频率为27.8%~53.1%,其中对Rps1k、Rps3a、Rps1c和Rps6基因的致病频率低于35%,对Rps7基因的致病频率为53.1%,说明在黑龙江东部种植含有Rps1k、Rps3a、Rps1c和Rps6基因的大豆品种较安全,种植含Rps7基因的大豆品种较危险。随时间推移黑龙江东部大豆疫霉生理小种和致病型分化迅速,致病型变得复杂多样,对绝大多数Rps基因致病频率增加,单株毒性和群体致病力均增强;生理小种和新致病型在试验田与生产田间数量差异不大,但种类差别较大,试验田单株毒性和群体致病力更强。

基于超分子自组装策略定性和定量检测奶粉中的三聚氰胺

三聚氰胺是一种应用广泛的化工原料,但在摄入人体后会形成结石,对肾功能造成极大损伤。由于其含氮量高,常被不法商家添加在奶粉中以提高奶粉含氮量,因此在食品工业中三聚氰胺的定性定量检测十分重要。本研究利用超分子自组装的策略,以三聚氰胺与氰尿酸自组装作用为基础,利用亚甲基蓝作为反应指示剂,使用操作便捷的分光光度法对奶粉中的三聚氰胺进行定性和定量检测。本方法反应条件温和、颜色变化明显、检出限低、灵敏度高,也可拆分成多个环节实验,应用于不同学时的实验教学,是一个适合本科教学环境的新颖实验。

Association of high expression in rat gastric mucosal heat shock protein 70 induced by moxibustion pretreatment with protection against stress injury

AIM:To study the effect of moxibustion on Zusanli or Liangmeng point on gastric mucosa injury in stress-induced ulcer rats and its correlation with the expression of heat shock protein 70 (HSP70). METHODS:Sixty healthy SD rats (30 males,30 females) were divided into control group,injury model group,Zushanli point group,Liangmeng point group. Stress gastric ulcer model was induced by binding cold stress method. Gastric mucosa ulcer injury (UI) index was calculated by Guth method. Gastric mucosa blood flow (GMBF) was recorded with a biological signal analyzer. Protein content and gene expression in gastric mucosal HSP70 were detected by immunohistochemistry (IHC) and reverse transcription polymerase chain reaction (RT-PCR). Thiobarbital method was used to determine malondialdehyde (MDA) content. Gastric mucosal endothelin (ET) and prostaglandin E2 (PGE2) were analyzed by radioimmunoassay. RESULTS:High gastric mucosal UI index,high HSP70 expression,low GMBF and PGF2,elevated MDA and ET were observed in gastric mucosa of rats subjected to cold stress. Moxibustion on Zusanli or Liangmeng point decreased rat gastric mucosal UI index,MDA and ET. Conversely,the expression of HSP70,GMBF,and PGE2 was elevated in gastric mucosa after pretreatment with moxibustion on Zusanli or Liangmeng point. The observed parameters were significantly different between Zusanli and Liangmeng points. CONCLUSION:Pretreatment with moxibustion on Zusanli or Liangmeng point protects gastric mucosa against stress injury. This protection is associated with the higher expression of HSP70 mRNA and protein,leading to release of PGE2 and inhibition of MDA and ET,impairment of gastric mucosal index.

RIP3/MLKL-mediated neuronal necroptosis induced by methamphetamine at 39℃

Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.

Flow behavior of Al-6.2Zn-0.70Mg-0.30Mn-0.17Zr alloy during hot compressive deformation based on Arrhenius and ANN models

The hot deformation behavior of Al?6.2Zn?0.70Mg?0.30Mn?0.17Zr alloy was investigated by isothermal compressiontest on a Gleeble?3500machine in the deformation temperature range between623and773K and the strain rate range between0.01and20s?1.The results show that the flow stress decreases with decreasing strain rate and increasing deformation temperature.Basedon the experimental results,Arrhenius constitutive equations and artificial neural network(ANN)model were established toinvestigate the flow behavior of the alloy.The calculated results show that the influence of strain on material constants can berepresented by a6th-order polynomial function.The ANN model with16neurons in hidden layer possesses perfect performanceprediction of the flow stress.The predictabilities of the two established models are different.The errors of results calculated by ANNmodel were more centralized and the mean absolute error corresponding to Arrhenius constitutive equations and ANN model are3.49%and1.03%,respectively.In predicting the flow stress of experimental aluminum alloy,the ANN model has a betterpredictability and greater efficiency than Arrhenius constitutive equations.

Role of the nucleus tractus solitarii in the protection of pre-moxibustion on gastric mucosal lesions

Previous studies have shown that somatic sensation by acupuncture and visceral nociceptive stimulation can converge in the nucleus tractus solitarii where neurons integrate signals impact- ing on the function of organs. To explore the role of the nucleus tractus solitarii in the protective mechanism of pre-moxibustion on gastric mucosa, nucleus tractus solitarii were damaged in rats and pre-moxibustion treatment at the Zusanli （ST36） point followed. The gastric mucosa was then damaged by the anhydrous ethanol lavage method. Morphological observations, enzyme linked immunosorbent assays, and western immunoblot analyses showed that gastric mucosa surface lesion and the infiltration of inflammatory cells were significantly ameliorated after pre-moxibustion treatment. Furthermore, the gastric mucosal damage index and somatostatin level were reduced, and epidermal growth factor content in the gastric mucosa and heat-shock protein-70 expression were increased. These results were reversed by damage to the nucleus tractus solitarii. These findings suggest that moxibustion pretreatment at the Zusanli point is protective against acute gastric mucosa injury, and nucleus tractus solitarii damage inhibits these responses. Therefore, the nucleus tractus solitarii may be an important area for regulating the signal transduction of the protective effect of pre-moxibustion on gastric mucosa.

Translation and validation of the Nepean Dyspepsia Index for functional dyspepsia in China

AIM： To assess the reliability and validity of the translated version of Nepean Dyspepsia Index （NDI） in Chinese patients with documented functional dyspepsia （FO）. METHODS： The translation process included forward translation, back translation, pretest and cross-cultural adaptation. Reliability and validity of the translated version were examined by asking 300 subjects to complete the Chinese version of the NDI. The mean age of subjects was 39.24 years and 68.7% of the subjects were women. Internal consistency analysis with Cronbach＇s α was performed to test the reliability. Correlation analysis was used to assess the content validity. Factor analysis and structural equation models were used to assess the construct validity. RESULTS： The Cronbach＇s α coefficients ranged 0.833-0.960, well above the acceptable level of 0.70. Correlation analysis showed that each item had a strong correlation with the corresponding domain, but a weak correlation with other domains. Confirmatory factor analysis indicated that the comparative fit index was 0.94, higher than the acceptable level of 0.90.CONCLUSION： The Chinese version of the NDI is a reliable and valid scale for measuring health-related quality of life and disease severity in Chinese patients with FD.

Diversity of Helicobacter pylori isolates in expression of antigens and induction of antibodies

AIM: To obtain evidence for selection of antigens used in genetically engineered vaccine against Helicobacter pylori (H pylori). METHODS: Enzyme linked immunoabsorbent assay (ELISA) was established on the basis of recombinant protein antigens rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB of H pylori to detect expression rates of the antigens in bacterial isolates as well as positive rates of the antibodies in sera from H pylori-infected patients. PCR was applied to the detection of carrying rates of the genes encoding antigens in the isolates. RESULTS: The outputs of rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB were approximately 35%, 32%, 15%, 23%, 56%, 25% and 20% of the total bacterial proteins, respectively. One hundred and fifty-one strains of H pylori were isolated from 347 biopsy specimens of chronic gastritis, peptic ulcer or gastric adenocarcinoma, with a positive rate of 43.5%. All of the isolates expressed UreB, HpaA, FlaA and FlaB while 52.3%, 92.1% and 93.4% of the isolates expressed VacA, CagA and NapA, respectively. In the sera of 151 H pylori-infected patients, the positive ratesof IgG antibodies against UreB, HpaA, VacA, CagA, NapA, FlaA and FlaB were 100%, 87.4%, 43%, 71.5%, 89.4%, 84.8% and 79.5%, respectively. Furthermore, the expression frequencies of VacA and NapA were found to be relative to the severity of gastric diseases (P = 0.016 and P < 0.0001, respectively). CONCLUSION: UreB antigen is the top option of developing genetically engineered vaccine against H pylori followed by NapA or HpaA.

A comprehensive review for wind,solar,and electrical load forecasting methods

Wind power,solar power,and electrical load forecasting are essential works to ensure the safe and stable operation of the electric power system.With the increasing permeability of new energy and the rising demand response load,the uncertainty on the production and load sides are both increased,bringing new challenges to the forecasting work and putting forward higher requirements to the forecasting accuracy.Most review/survey papers focus on one specific forecasting object(wind,solar,or load),a few involve the above two or three objects,but the forecasting objects are surveyed separately.Some papers predict at least two kinds of objects simultaneously to cope with the increasing uncertainty at both production and load sides.However,there is no corresponding review at present.Hence,our study provides a comprehensive review of wind,solar,and electrical load forecasting methods.Furthermore,the survey of Numerical Weather Prediction wind speed/irradiance correction methods is also included in this manuscript.Challenges and future research directions are discussed at last.

血清神经元特异性烯醇化酶和尿香草扁桃酸与神经母细胞瘤临床病理特征的相关性

目的:分析神经母细胞瘤(neuroblastoma,NB)患儿治疗前血清神经元特异性烯醇化酶(neuron-specific enolase,NSE)和尿香草扁桃酸(vanillymandelic acid,VMA)的水平,比较二者与NB临床病理特征的相关性以及二者预测高危组患儿的能力,为更好地诊断和评估病情提供依据。方法:收集2011年9月至2019年9月天津医科大学肿瘤医院确诊的155例NB患儿的临床病理资料。回顾性分析不同临床特征的患儿血清NSE和尿VMA水平,包括年龄、性别、肿瘤体积及部位、病理类型、INSS分期、危险度分组、是否转移、MYCN基因扩增及有无IDRFs情况。采用非参数秩和检验比较组间差异,P<0.05为差异具有统计学意义。为比较血清NSE和尿VMA在高危组患儿中的诊断价值,绘制ROC曲线,建立预测模型,比较二者鉴别高危组患儿的准确性。结果:109例患儿检测尿VMA,其中阴性61例,阳性48例,阳性率44.0%。152例患儿检测血清NSE,其中阴性2例,阳性150例,阳性率98.7%。血清NSE和尿VMA水平在INSS 4期、COG高危组、伴有转移和有IDRFs的患儿中均显著增高(P<0.05)。血清NSE在肿瘤部位、肿瘤体积和病理类型不同的患儿中具有显著性差异;肿瘤体积>500 cm3、INPC预后不良,病理类型为NB,原发灶位于腹膜后的患儿,血清NSE水平显著高于其他组(P<0.001)。ROC曲线结果显示血清NSE鉴别高危组患儿的界值为98.50 ng/mL,曲线下面积AUC为0.943(95%CI:0.906~0.991)。尿VMA鉴别高危组患儿的界值为62.28μmoL/24 h,AUC为0.791(95%CI:0.705~0.878)。联合二者鉴别高危组患儿,AUC为0.948(95%CI:0.900~0.997)。结论:与尿VMA相比,血清NSE与更多的NB临床特征相关,可以更全面地辅助诊断疾病及评估病情。在高危组患儿中,血清NSE和尿VMA水平均显著增高。NSE鉴别高危组患儿的准确性、灵敏度和特异度均高于尿VMA,二者联合检测并不能提高诊断的准确性。

Rapid Detection of rpoB Gene Mutations in Rif-resistant M.tuberculosis Isolates by Oligonucleotide Microarray

Objective To detect the specific mutations in rpoB gene of Mycobacterium tuberculosis by oligonucleotide microarray. Methods Four wild-type and 8 mutant probes were used to detect rifampin resistant strains. Target DNA of M. tuberculosis was amplified by PCR, hybridized and scanned. Direct sequencing was performed to verify the results of oligonucleotide microarray Results Of the 102 rifampin-resistant strains 98 （96.1%） had mutations in the rpoB genes. Conclusion Oligonucleotide microarray with mutation-specific probes is a reliable and useful tool for the rapid and accurate diagnosis of rifampin resistance in M. tuberculosis isolates.

CagA^+ H.pylori Induces Akt1 Phosphorylation and Inhibits Transcription of p21^(WAF1/CIP1) and p27^(KIP1) via PI3K/Akt1 Pathway

Objective Cytotoxin-associated protein （CagA） of H. pylori has been confirmed to be closely associated with gastric inflammation and tumorigenesis, but the mechanism behind it is little understood. In this study, we try to determine roles of CagA＋ strain in activating PI3K/Akt1 signaling pathway, and affecting expression of p21WAF1/CIP1 and p27KIP1, and also in releasing IL-8 in host cells. Methods Akt1 phosphorylation and IL-8 levels of CagA＋ and CagAˉ strain infected AGS cells were detected by ELISAs. Two quantitative RT-PCRs were established to measure p21WAF1/CIP1 and p27KIP1 mRNA levels in the CagA＋ and CagAˉ strain infected cells. LY294002, an inhibitor of PI3K/Akt pathway, was used to define effect of the pathway in IL-8 release. Results CagA＋ strain could induce an obvious elevation of Akt1 phosphorylation in the infected AGS cells while CagAˉ strain failed to do so. The CagA＋ H. pylori strain infected AGS cells showed significant drops both in p21WAF1/CIP1 and p27KIP1 mRNA levels, whereas the CagAˉ H. pylori strain caused a remarkable increase in p21WAF1/CIP1 mRNA without affecting p27KIP1 gene transcription in the AGS cells. Both the CagA＋ and CagAˉ H. pylori strains enabled AGS cells to produce close elevated levels of IL-8, and the LY294002 block resulted in unexpected elevations of IL-8 levels. Conclusion CagA can activate PI3K/Akt1 pathway that plays an inhibitory role in IL-8 release in H. pylori infected AGS cells. Activation of PI3K/Akt1 pathway and subsequent negative regulation of p21^WAF1/CIP1 and p27^KIP1 expression might be involved in CagA-associated carcinogenesis.

儿童横纹肌肉瘤复发及预后的影响因素分析

目的:探讨横纹肌肉瘤(rhabdomyosarcoma,RMS)的复发及预后的影响因素。方法:回顾性分析2000年1月至2017年10月天津医科大学肿瘤医院儿童肿瘤科收治的91例RMS患儿的临床病理资料。采用单因素χ~2检验或Fisher确切概率法和Logistic回归分析影响RMS复发的危险因素,并采用Kaplan-Meier法及Cox风险模型对RMS复发患儿进行预后影响因素分析。结果:RMS复发率为41.8%,复发组38例患儿1、3、5年生存率分别为97.4%、52.9%、27.8%。患儿的临床分期、危险度分组、是否伴有转移及是否规范化疗是影响RMS患儿复发的危险因素,其中是否规范化疗是影响复发的独立危险因素(P<0.05)。生存分析表明复发时间及是否伴有转移与RMS复发患儿的预后相关,且均为独立影响因素(P<0.05)。结论:进行规范化疗有助于降低RMS的复发率,复发时间及是否伴有转移与复发患儿预后相关。

Optimal two-iteration sculling compensation mathematical framework for SINS velocity updating

A new two-iteration sculling compensation mathematical framework is provided for modern-day strapdown inertial navigation system（SINS） algorithm design that utilizes a new concept in velocity updating. The principal structure of this framework includes twice sculling compensation procedure using incremental outputs from the inertial system sensors during the velocity updating interval. Then, the moderate algorithm is designed to update the velocity parameter. The analysis is conducted in the condition of sculling motion which indicates that the new mathematical framework error which is smaller than the conventional ones by at least two orders is far superior. Therefore, a summary is given for SINS software which can be designed with the new mathematical framework in velocity updating.

Quantitative method for evaluating detailed volatility of wind power at multiple temporal-spatial scales

With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to evaluate the volatility of wind power only consider its overall characteristics, such as the standard deviation of wind power, the average of power variables, etc., while ignoring the detailed volatility of wind power, that is, the features of the frequency distribution of power variables. However, how to accurately describe the detailed volatility of wind power is the key foundation to reduce its adverse influences. To address this, a quantitative method for evaluating the detailed volatility of wind power at multiple temporal-spatial scales is proposed. First, the volatility indexes which can evaluate the detailed fluctuation characteristics of wind power are presented, including the upper confidence limit, lower confidence limit and confidence interval of power variables under the certain confidence level. Then, the actual wind power data from a location in northern China is used to illustrate the application of the proposed indexes at multiple temporal(year–season–month–day) and spatial scales(wind turbine–wind turbines–wind farm–wind farms) using the calculation time windows of 10 min, 30 min, 1 h, and 4 h. Finally, the relationships between wind power forecasting accuracy and its corresponding detailed volatility are analyzed to further verify the effectiveness of the proposed indexes. The results show that the proposed volatility indexes can effectively characterize the detailed fluctuations of wind power at multiple temporal-spatial scales. It is anticipated that the results of this study will serve as an important reference for the reserve capacity planning and optimization dispatch in the electric power system which with a high proportion of renewable energy.

Aqueous angiopoietin-like levels correlate with optical coherence tomography angiography metrics in diabetic macular edema

AIM:To quantitatively detect aqueous levels of angiopoietin-like(ANGPTL)3,ANGPTL4,and ANGPTL6 and investigate their correlation with optical coherence tomography angiography(OCTA)findings in patients with diabetic macular edema(DME).METHODS:This cross-sectional study included 23 patients(27 eyes)with type 2 diabetes and 16 control subjects(20 eyes).All patients underwent OCTA imaging and ultra-wide field fundus photography.Diabetic patients were categorized into two groups according to the presence or absence of diabetic retinopathy(DME group,14 patients,16 eyes);and non-diabetic retinopathy(NDR)group,9 patients,11 eyes,respectively.Aqueous levels of ANGPTL3,ANGPTL4,and ANGPTL6 were assessed using suspension array technology,and foveal-centered 3×3 mm2 OCTA scans were automatically graded to determine the central,inner,and full vessel density(CVD,IVD,FVD);central,inner,and full perfusion density(CPD,IPD,FPD),foveal avascular zone(FAZ)area,FAZ perimeter,and FAZ circularity index(FAZ-CI)on superficial capillary plexuses.Additionally,central subfield thickness(CST),cube volume(CV),and cube average thickness(CAT)were measured in a model of macular cube 512×128.RESULTS:Aqueous ANGPTL3 levels were not significantly different among the three groups(P>0.05).ANGPTL4 levels were significantly higher in the DME group than the control and NDR groups(P<0.0001 and P<0.001),while ANGPTL6 levels were significantly higher in the DME group than the control group(P<0.05).In the whole cohort,the aqueous ANGPTL3 levels correlated negatively with the IVD,FVD,IPD,and FPD,and positively with the CV and CAT.The aqueous ANGPTL4 levels correlated negatively with the CVD,IVD,FVD,CPD,IPD,and FPD,and positively with the FAZ perimeter,CST,CV,and CAT.The aqueous ANGPTL6 levels correlated negatively with the IVD,FVD,IPD,FPD,FAZCI and positively with CST,CV,CAT.CONCLUSION:ANGPTL4 and ANGPTL6 may be associated with vascular leakage in DME and may represent good targets for DME therapy.In addition,OCTA metrics may be useful for evaluating macular ischemia in DME.

Screening for metronidazole-resistance associated gene fragments of H pylori by suppression subtractive hybridization

AIM： To screen for metronidazole （MTZ）-resistance associated gene fragments of H pylori by suppression subtractive hybridization （SSH）. METHODS： Five MTZ-resistant （tester, T） and 1 MTZ- susceptible （driver, D） clinical H pylori isolates were selected. Genomic DNAs were prepared and submitted to Rsa I digestion. Then two different adaptors were ligated respectively to the 5＇-end of two aliquots of the tester DNA fragments and SSH was made between the tester and driver DNAs. The specific inserts of tester strains were screened and MTZ-resistance related gene fragments were identified by dot blotting. RESULTS： Among the randomly selected 120 subtractive colonies, 37 DNA fragments had a different number of DNA copies （≥ 2 times） in resistant and susceptible strains and 17 of them had a significantly different number of DNA copies （≥ 3 times）. Among the sequences obtained from the 17 DNA fragments, new sequences were found in 10 DNA fragments and duplicated sequences in 7 DNA fragments, representing respectively the sequences of depeptide ABC transporter periplasmic dipeptide-binding protein （dppA）, permease protein （dppB）, ribosomal protein S4 （rps4）, ribonuclease Ⅲ （rnc）, protease （pqqE）, diaminopimelate epimerase （dapF）, acetatekinase （ackA）, H pylori plasmid pHP51 and Hpylori gene 1334. CONCLUSION： Gene fragments specific to MTZ-resistant H pylori strains can be screened by SSH and may be associated with MTZ-resistant Hpylori.

长链非编码RNA 00682通过调节MYCN表达促进神经母细胞瘤的增殖和转移能力

目的:研究神经母细胞瘤中长链非编码RNA 00682(LINC00682)的表达与MYCN表达量之间的关系,以及LINC00682调节神经母细胞瘤功能的机制。方法:收集2009年12月至2019年12月天津医科大学肿瘤医院104例不同分期的神经母细胞瘤临床标本及其病理及预后信息,通过实时荧光定量PCR检测LINC00682在临床标本和神经母细胞瘤细胞系的表达并分析其表达量与临床病理特征及预后的关系。在SK-N-Be2和SK-N-AS细胞系中应用小干扰RNA抑制LINC00682表达,进一步利用CCK-8和生长曲线检测其增殖能力,利用划痕实验和侵袭实验检测其转移能力,并在SK-N-Be2细胞系中检测MYCN的表达。结果:实时定量PCR检测104例神经母细胞瘤临床标本发现LINC00682在高危组的表达量明显高于低危组和中危组,分析临床信息得出LINC00682的表达与肿瘤转移、病理类型,临床分期和患者预后相关。在5种神经母细胞瘤细胞系中,LINC00682在MYCN扩增细胞系SK-N-Be2和IMR-32的表达水平显著高于非MYCN扩增细胞系SK-N-AS、SK-N-SH和SH-SY5Y。应用实时荧光定量PCR检测48例神经母细胞瘤临床标本中LINC00682和MYCN的表达,两者呈正相关。应用小干扰RNA抑制LINC00682在SK-N-Be2和SK-N-AS中的表达后,神经母细胞瘤细胞的增殖和转移能力明显下降,同时在SK-N-Be2细胞系MYCN的mRNA和蛋白水平均受到抑制。结论:LINC00682的高表达与神经母细胞瘤的肿瘤转移、病理类型,临床分期和预后相关,并且LINC00682可能通过影响MYCN的表达促进神经母细胞瘤细胞的增殖和转移。