The inhibitory effects of oxytocin on distal colonic contractile activity in rabbits are enhanced by ovarian steroids

Aims: To study the effects of oxytocin on isolated rabbit distal colon and the regulation of ovarian steroids by its action. Methods: Muscle strips parallel to either the circular or the longitudinal fibres were excised and suspended in tissue chambers containing 5 mL Krebs solution (37 °C) and bubbled continuously with 95% O₂ and 5% CO₂. The effects of oxytocin on isometric spontaneous contractile responses were recorded. The effects of atosiban, tetrodotoxin, Mg²⁺, progesterone and oestradiol on the oxytocin‐induced response were also examined. Results: Oxytocin (1, 10 and 100 nmol L^?1) dose dependently decreased the area under the contraction curve of distal colonic smooth muscle strips. The oxytocin receptor antagonist atosiban blocked the oxytocin (10 nmol L^?1)‐caused responses in a dose‐dependent manner. Tetrodotoxin (10 μmol L^?1) had no effect on the oxytocin‐induced response. Mg²⁺‐free Krebs solution attenuated the oxytocin‐induced response, but oestradiol (0.1 μmol L^?1) or progesterone (0.1 μmol L^?1) increased the oxytocin‐induced response. Conclusion: These results suggest that oxytocin inhibits the contractile motility of the distal colon, which is regulated by Mg²⁺ and ovarian steroids.     

组织工程化肌腱种子细胞深低温保存的实验研究

对肌腱种子细胞进行深低温保存，研究保存过程中多个环节的影响因索对细胞存活率的影响及深低温保存对种子细胞生物学特性、胶原分泌功能的影响。实验结果表明二甲基亚砜是肌腱种子细胞深低温保存中比较好的抗冻保护剂；冻存后使用与培养时不同的营养血清处理对细胞有损害，可降低细胞存活率；在冷冻保存过程中，细胞存活率与细胞浓度有一定关系，浓度太低可能降低细胞存活率；细胞在冷冻保存时，降温速度对细胞存活率有影响，慢速的分步降温组细胞存活率明显高于直接人液氮的快速降温组；采用10％二甲基亚砜加15%小牛血清加75% DMEM配方保存肌腱种子细胞，对其分泌胶原功能无明显影响，对其生长曲线、细胞周期及染色体众数无明显改变，适于肌腱种子细胞的保存。     

聚乙二醇在聚砜膜上的接枝与表征

对用紫外辐照法在聚砜膜表面接枝的聚乙二醇作了初步的研究。通过静态水接触角测定、X射线-光电子能谱分析以及原子力学显微镜等测试手段，对接枝前后聚砜膜表面的性能进行了测定，证明采用同步接枝法和二步接枝法在聚砜材料表面接上了聚乙二醇，表面亲水性大大提高，两种接枝方法的接枝覆盖率分别为77．3％和41．9％，表面形貌、相位图等参数较接枝前变化明显，说明用同步法在聚砜膜表面产生了分枝的聚乙二醇层，而二步法在聚砜膜表面产生了薄煎饼状的聚乙二醇层。这一研究为下一步拟在聚砜中空纤维膜表面接上聚乙二醇刷分子层打下了基础。     

网织红细胞膜生物物理特性的研究

用苯肼使动物造成急性溶血性贫血的方法，诱发动物体内新生网织红细胞大量增多，通过对新生网织红细胞的电泳率、渗透脆性、膜的流动性等生物物理指标连续72h的测量，发现网织红细胞在由网织红细胞转变为成熟红细胞的过程中．其生物物理特性有明显改变。这对研究由于贫血等原因造成的网织红细胞增多情况下，全血的微观流变学特性具有重要的临床意义，同时对新生网织红细胞膜的生物物理特性加以系统研究，具有重要的基础理论研究价值。     

军医大学研究生应对方式特征及其与自测健康状况的相关分析

目的 了解军医大学研究生的应对方式特征及其与自测健康状况的关系。方法 采用随机整群抽样法,选择广州市某军医大学在读硕士研究生189名,应用简易应对方式问卷和自刹健康评定量表进行调查。结果 军医大学研究生采取积极应对方式的比例（34.86％）明显高于采取消极应对方式的比例（10．56％）．最常采取的应对方式是“通过工作学习或一些其他活动解脱（51．4％）”、“尽量看到事物好的一面（46．4％）”和“不把问题看得太严重（40．9％）”;最不常采用的应对方式为“依靠别人解决问题（0．6％）”、“幻想奇迹发生（2．8％）”等;积极应对方式得分与自测健康的生理、心理、社会子量表得分和总分呈显著正相关。消极应对方式得分与自测健康的生理、心理于量表得分和总分呈显著负相关。结论 不同应对方式对自测健康的影响作用不同,积极应时方式有助于军医大学研究生的身心健康,消极应对则有负面影响。     

Enhanced immunogenicity and antitumour effects with heterologous prime-boost regime using vaccines based on MG7-Ag mimotope of gastric cancer

MG7-Ag, gastric cancer-associated antigen, has been shown to be immunogenic and has been used as marker molecule for prognosis. In a previous study, we developed an oral DNA vaccine based on MG7-Ag mimotope. However, we failed to detect cellular immune response using the oral MG7-Ag mimotope DNA vaccine. To induce significant T cell response, we developed a recombinant adenovirus vaccine based on MG7-Ag mimotope and evaluated the efficacy and protective effects of heterologous prime-boost immunization protocol with an oral DNA vaccine previously developed. We found that both vaccines were able to elicit a significant humoral response against MG7-Ag, while the highest serum titre MG7 antibody was detected in mice immunized with the heterologous prime-boost immunization protocol. Enzyme-linked immunospot (ELISPOT) assay demonstrated that the heterologous prime-boost immunization strategy was more efficient in inducing T cell response than the homologous prime-boost strategy. In the tumour challenge assay, 2 of 5 mice immunized with the heterologous prime-boost protocol were tumour free, while none of the mice in homologous prime-boost groups or control groups was tumour free. Those tumour-bearing mice in the heterologous prime-boost regime had smaller tumour masses than their counterparts in the homologous prime-boost groups or control groups. Therefore, our study suggests that vaccines against MG7-Ag induce significant immune response against gastric cancer, and that the heterologous prime-boost protocol using different types of vaccines could achieve better protective effect than the homologous prime-boost protocol.     

Correlation between gag-specific CD8 T-cell responses, viral load, and CD4 count in HIV-1 infection is dependent on disease status

BACKGROUND: It still remains controversial which kind of relationships exist between HIV-1-specific CD8 T-cell responses and HIV RNA load or CD4 count over the course of the infection. This study was designed to investigate the role of HIV-specific CD8 responses in patients with different disease status. METHODS: Three cohorts of patients were selected according to CD4 count levels: long-term nonprogressors (LTNPs, n = 19), asymptomatic progressors (CD4 counts between 500 and 350 cells/mm(3), n = 14), and progressors (CD4 counts <350 cells/mm(3), n = 23). Six of the LTNPs experiencing a quick loss of CD4 T-cells and another 6 LTNPs with stable CD4 counts were followed up. T-cell responses were studied using interferon (IFN) gamma-ELISpot assay against HIV p24 and 11 pools of HIV-Gag peptides. RESULTS: No significant differences were found in Gag-specific CD8 responses among the 3 cohorts. However, inverse correlations were identified between CD8 responses and CD4 counts in asymptomatic progressors and between CD4 responses and viral loads in progressors. In addition, the sequential dynamics of CD8 responses in 6 LTNPs showed that with a quick loss of CD4 T-cells around the range of 500 to 300 cells/mm(3), more vigorous CD8 responses were induced simultaneously, and plasma viremia was still kept relatively stable. CONCLUSIONS: These data suggest that the relationship between CD8 response and viral load or CD4 count is not universally consistent throughout the entire course of HIV-1 infection. Gag-specific CD8 responses may play differential roles in different stages of HIV-1 infection, and the maintenance of a threshold level of CD4 T-cells may contribute to mediate effective HIV-specific responses in natural control of HIV-1 infection.     

SHP-2 phosphatase negatively regulates the TRIF adaptor protein-dependent type I interferon and proinflammatory cytokine production

The Toll-like receptor 3 (TLR3) and TLR4-signaling pathway that involves the adaptor protein TRIF activates type I interferon (IFN) and proinflammatory cytokine expression. Little is known about how TRIF pathway-dependent gene expression is regulated. SH2-containing protein tyrosine phosphatase 2 (SHP-2) is a widely expressed cytoplasmic tyrosine phosphatase. Here we demonstrate that SHP-2 negatively regulated TLR4- and TLR3-activated IFN-beta production. SHP-2 inhibited TLR3-activated but not TLR2-, TLR7-, and TLR9-activated proinflammatory cytokine IL-6 and TNF-alpha production. SHP-2 inhibited poly(I:C)-induced cytokine production by a phosphatase activity-independent mechanism. C-terminal domain of SHP-2 directly bound TANK binding kinase (TBK1) by interacting with the kinase domain of TBK1. SHP-2 deficiency increased TBK1-activated IFN-beta and TNF-alpha expression. TBK1 knockdown inhibited poly(I:C)-induced IL-6 production in SHP-2-deficient cells. SHP-2 also inhibited poly(I:C)-induced activation of MAP kinase pathways. These results demonstrate that SHP-2 specifically negatively regulate TRIF-mediated gene expression in TLR signaling, partially through inhibiting TBK1-activated signal transduction.     

Identification of new genetic regions more prevalent in nontypeable Haemophilus influenzae otitis media strains than in throat strains

Nontypeable (NT) Haemophilus influenzae strains cause significant respiratory illness and are isolated from up to half of middle ear aspirates from children with acute otitis media. Previous studies have identified two genes, lic2B and hmwA, that are associated with NT H. influenzae strains isolated from the middle ears of children with otitis media but that are not associated with NT H. influenzae strains isolated from the throats of healthy children, suggesting that they may play a role in virulence in otitis media. In this study, genomic subtraction was used to identify additional genetic regions unique to middle ear strains. The genome of NT H. influenzae middle ear strain G622 was subtracted from that of NT H. influenzae throat strain 23221, and the resultant gene regions unique to the middle ear strain were identified. Subsequently, the relative prevalence of the middle ear-specific gene regions among a large panel of otitis media and throat strains was determined by dot blot hybridization. By this approach, nine genetic regions were found to be significantly more prevalent in otitis media strains. Classification tree analysis of lic2B, hmwA, and the nine new potential otitis media virulence genes revealed two H. influenzae pathotypes associated with otitis media.     

围产期母亲和胎儿心动周期信号分析

同时分析围产期胎儿和孕妇心动周期信号的数字特征(混沌和谱特征)以评价自主神经系统功能。用可视化程序设计的方法实现提取和分析围产期母亲和胎儿心动周期信号。受试者取仰卧位，心电信号从置于腹壁下部耻骨联合导联获得。胎儿心电信号用小波分解进行信号预处理。采用本实验室已经完成开发的技术实现心动周期信号数字特征的分析。该系统可以评价胎儿和孕妇的自主神经系统功能，特别是分别定量评价交感和副交感神经系统功能；该系统还可用以预测胎儿窘迫。胎儿和其它年龄段的心动周期信号数字特征随年龄的变化提示了自主神经系统的发育、成熟和衰老的生理过程，基于这一点我们可以寻找抗衰老的方法；胎儿的心动周期信号数字特征介于新生儿和成人之间，提示胎儿的自主神经系统的调节可能受母体神经内分泌系统的影响。