Trans-suppression of defense DEFB1 gene in intestinal epithelial cells following Cryptosporidium parvum infection is associated with host delivery of parasite Cdg7_FLc_1000 RNA

Parasitology Research - To counteract host immunity, Cryptosporidium parvum has evolved multiple strategies to suppress host antimicrobial defense. One such strategy is to reduce the production of...     

Genomic characterization of a bovine viral diarrhea virus 1 isolate from swine

The SD0803 strain of the bovine viral diarrhea virus (BVDV) was isolated from a piglet in China in 2008 and has been classified as a novel subgenotype of BVDV-1. To describe the molecular features of this novel subgenotype, we sequenced and characterized the complete genome of the SD0803 virus. The genome is 12,271 bp in length and contains 5′ and 3′ untranslated regions (UTRs) that flank an open reading frame (ORF) encoding a 3,898-amino-acid polypeptide. The full-length genome of the SD0803 strain shares 78.8 % to 83.3 % identity with those of other BVDV-1 strains, 70.0 % to 70.7 % identity with those of BVDV-2 strains, and less than 67.6 % identity with those of other pestiviruses. The highest level of shared identity was 83.3 % between the complete SD0803 genome and that of the ZM-95 strain of BVDV-1. Phylogenetic analysis of the 5′ UTR and the coding sequence for the N-terminal protease fragment of the SD0803 polyprotein indicated that the SD0803 virus is a member of the novel subgenotype BVDV-1q, isolates of which have been identified recently in dairy cattle and camels in China.     

Effect of Tempering Temperature on Microstructure and Sulfide Stress Cracking of 125 Ksi Grade Casing Steel

The influence of tempering temperature on the microstructure of 0.5Cr0.4W steels was investigated by scanning electron microscope, and the roles of grain boundary character, dislocation, and Taylor factor in sulfide stress cracking (SSC) resistance were interpreted using the election backscattered diffraction technique. The 0.5Cr0.4W steels tempered at 690 °C, 700 °C, and 715 °C all showed tempered martensites. The specimen tempered at 715 °C exhibited a higher critical stress intensity factor (K_ISSC) of 34.58 MPa·m^0.5, but the yield strength of 800 MPa did not meet the criterion of 125 ksi (862 MPa) grade. When the specimen was tempered at 690 °C, the yield strength reached 960 MPa and the K_ISSC was only 21.36 MPa·m^0.5, displaying poorer SSC resistance. The 0.5Cr0.4W steel tempered at 700 °C showed a good combination of yield strength (887 MPa) and SSC resistance (K_ISSC: 31.16 MPa·m^0.5). When increasing the tempering temperature, the local average misorientation and Taylor factor of the 0.5Cr0.4W steels were decreased. The reduced dislocation density, and greater number of grains amenable to slippage, produced less hydrogen transport and a lower crack sensitivity. The SSC resistance was, thus, increased, owing to the minor damage to hydrogen aggregation. Therefore, 700 °C is a suitable tempering temperature for 0.5Cr0.4W casing steel.     

中药芪参复康对焦虑模型大鼠β-EP及细胞因子的影响

目的：对中药芪参复康（QSFK）胶囊抗焦虑作用的神经-免疫调节机制进行初步探讨．方法：采用国际通用的高架十字迷宫模型（EPM）焦虑动物模型,用丁螺环酮（Bus）作对照,观察QSFK对EPM大鼠β-EP,血清NO,IL-1β,IL-6和TNFα的影响．结果：与模型组比较,QSFK和Bus均能降低EPM大鼠血浆β-EP含量（P〈0.01）,对下丘脑β-EP水平无明显影响;但两组均能升高EPM焦虑模型大鼠血清NO水平（P〈0．05）：QSFK还可升高EPM大鼠血清IL-1β和TNFα水平,对IL-6含量无明显影响;Bus并不能改变此焦虑模型大鼠的血清细胞因子水平．结论：QSFK降低血浆β-EP含量,提高血清NO浓度和EPM血清IL-1β和TNFα水平,以调节焦虑状态下机体免疫功能紊乱．     

Genetic analysis revealed LX4 genotype strains of avian infectious bronchitis virus became predominant in recent years in Sichuan area,China

Between 2008 and 2010, 19 strains of infectious bronchitis virus (IBV) were isolated from the vaccinated chicken flocks in Sichuan province, China. The S1 genes of the isolates were amplified and sequenced. Phylogenetic analysis revealed that the 19 isolates and 37 reference IBV strains can be grouped into eight genotypes. Although IBVs of Taiwan-I type, massachusetts type, and proventriculitis type were isolated, but most isolates were LX4 genotype. Homology analysis of the sequences of S1 genes of the 19 isolates and 37 reference IBV strains revealed that the identity of the nucleotides and amino acid sequences of the S1 genes between the 15 LX4-type isolates and other IBV strains were 71.9–99.3% and 72.1–99.1%, respectively, while those of the analyzed IBV of LX4 type were 96.0–99.9% and 94.3–99.8%, respectively. The results from this study and other published results in the GenBank database showed that isolates circulating in Sichuan province in recent years were mainly LX4 genotype, which is the predominant genotype circulated in China in recent years.     

Involvement of ER-α36, Src, EGFR and STAT5 in the biphasic estrogen signaling of ER-negative breast cancer cells

It is well established that estrogen is a potent mitogen in cells expressing estrogen receptors (ER). However, a large body of evidence has demonstrated that the effects of mitogenic estrogen signaling exhibit a non-monotonic or biphasic, dose-response curve; estrogen at low concentrations, elicits a mitogenic signaling pathway to stimulate cell proliferation, while at high concentrations, estrogen inhibits cell growth. The molecular mechanism underlying this paradoxical effect of estrogen on cell proliferation remains largely unknown. Recently, we reported that ER-α36, a variant of ER-α, mediates mitogenic estrogen signaling in ER-negative breast cancer cells. Here, we investigated the molecular mechanisms underlying the biphasic estrogen signaling in MDA-MB-231 and MDA-MB-436 ER-negative breast cancer cells. We found that 17β-estradiol (E2β) at l nM induced the phosphorylation of Src-Y416, an event that activates Src, while at 5 μM failed to induce Src-Y416 phosphorylation but induced Src-Y527 phosphorylation an event that inactivates Src. E2β at 1 nM, but not at 5 μM, also induced phosphorylation of MAPK/ERK and activated Cyclin D1 promoter activity through the Src/EGFR/STAT5 pathway. Knockdown of ER?α36 abrogated the biphasic estrogen signaling in these cells. Our results thus indicate that in ER-negative breast cancer cells Src functions as a switch in ER?α36-mediated biphasic estrogen signaling through the EGFR/STAT5 pathway.     

口服益生菌对早产儿肠道耐药菌定植的影响

目的 探讨NICU 中早产儿口服益生菌对肠道耐药菌定植的影响。方法 将生后立即入住NICU的早产儿以是否母乳喂养分层后随机分组,试验组从开始胃肠内营养之日起添加益生菌喂养,对照组为空白对照。比较两组生后第1、3、7、14 天直肠拭子产超广谱β 内酰胺酶（ESBL）耐药菌筛查结果及疾病发生情况。结果 试验组（n=119）与对照组（n=138）在第1、3、7、14 天的直肠耐药菌定植及晚发性败血症、坏死性小肠结肠炎等疾病发生的差异均无统计学意义（P>0.05）。试验组非母乳喂养患儿生后第14 天的直肠耐药菌定植率明显低于对照组非母乳喂养儿（ 71.1% vs 88.9%,P=0.04）。未观察到益生菌使用相关不良反应发生。结论 早产儿使用益生菌一定条件下可能减少直肠耐药菌定植,且具有较高安全性。     

Tet-off系统对小鼠骨髓基质细胞中人IFN-γ基因表达的调控作用

背景与目的:本实验室已成功构建了质粒pTre-IFN-γ,并证实四环素基因调控系统(Tet-off system)能在体外调控人γ-干扰素(interferon-gamma,IFN-γ)基因在小鼠骨髓基质细胞(marrow stromal cells,MSCs)中的表达。本实验进一步研究Tet-off系统体外调控的可逆性,以及其对小鼠MSCs中人IFN-γ基因表达的调控作用。方法:脂质体介导pTet-off和pTre-IFN-γ质粒共转染小鼠MSCs。用ELISA法检测MSCs培养液中人IFN-γ蛋白的分泌量。把共转染后的MSCs回输给BALB/c裸小鼠,用实时荧光定量RT-PCR方法检测各组BALB/c裸小鼠脾组织中的IFN-γmRNA含量。结果:用ELISA法可检测到共转染后的MSCs培养液中有IFN-γ蛋白分泌,分泌高峰在前72h内;共转染后84h加入含300ng/mL盐酸四环素的培养液培养12h,每1×107个细胞的分泌量为(67.11±22.14)pg,无四环素处理组为(319.96±29.04)pg,两组相比差异有统计学意义(P<0.001);去除四环素后,IFN-γ蛋白分泌显著增加(P=0.032)。用实时荧光定量RT-PCR可检测到回输共转染MSCs的各组BALB/c裸小鼠脾组织中均有IFN-γmRNA转录,不用四环素处理组最高,达(1.5±0.7)×105copy·(100mg)-1,定期四环素处理组为(6.9±5.3)×102copy·(100mg)-1(P<0.001),接受1次四环素处理组表达量介于前两者之间,差异均有统计学意义(P<0.01)。结论:Tet-off系统在体外和体内都可以迅速、有效地调控人IFN-γ基因在小鼠MSCs中的表达,而且调控是可逆的。     

保留旋前方肌掌侧微创入路治疗老年桡骨远端骨折的效果

目的对比保留旋前方肌掌侧微创入路与传统Henry入路治疗老年桡骨远端骨折的临床疗效。方法选取2016年1月至2019年1月在航天中心医院骨科住院治疗的老年桡骨远端骨折患者46例进行回顾性分析。依据治疗方法分为2组:微创组和对照组,每组各23例。微创组采取保留旋前方肌掌侧微创入路锁定钢板螺钉内固定术;对照组采取传统切开旋前方肌Henry掌侧入路钢板螺钉内固定术。比较2组患者手术切口长度、术中出血量、手术并发症、术后住院时间、骨折复位情况(掌倾角和尺偏角)及术后3个月腕关节功能恢复情况。采用SPSS 20.0软件进行数据处理。依据数据类型,组间比较采用t检验或χ~2检验。结果与对照组相比,微创组患者的切口长度[(2.4±0.3)和(7.2±1.4)cm]、术中出血量[(13.2±2.1)和(31.2±4.1)ml]和术后住院时间[(4.6±0.9)和(7.5±1.2)d]均显著减少(P0.05)。2组患者术后均未发生手术并发症。微创组患者术后3个月的视觉模拟量表(VAS)评分显著低于对照组[(0.5±0.2)和(2.2±0.4)分,P0.05],而Gartland-Werley评分达优率(95.65%和73.91%)和腕关节旋前角度(83.8°±10.8°和74.6°±9.5°)均显著高于对照组(P0.05)。结论保留旋前方肌掌侧微创入路钢板螺钉内固定治疗老年桡骨远端骨折的疗效较好,且手术切口小,术中出血量少,术后3个月腕关节整体功能恢复好。     

Maze model to study spatial learning and memory in freely moving monkeys

Many types of mazes have been used in cognitive brain research and data obtained from those experiments, especially those from rodents' studies, support the idea that the hippocampus is related to spatial learning and memory. But the results from non-human primates researches regarding the role of the hippocampus in spatial learning and memory are controversial and inconsistent with those obtained in rodents. This might be due to the differences of the methods used in non-human primates and rodents. Several kinds of maze models including two-dimensional computerized visual maze models and three-dimensional maze models have been developed for non-human primates, but they all have some defects. Therefore, development of a maze model for non-human primates that is comparable with those used in rodents is necessary to solve the controversy. This paper describes a large-scale, three-dimensional outdoor maze model for non-human primates which can be used to study spatial learning and memory. Monkeys learn to use the maze quickly compared with two-dimensional computerized visual mazes. It has many advantages which could make up the limits of the existing three-dimensional mazes in non-human primates, and can be comparable with radial arm mazes used in rodents. Based on the results, we believe that the new maze model will be valuable in many research areas, especially in studies involving spatial learning and memory in freely moving monkeys.