The type IC hsd loci of the enterobacteria are flanked by DNA with high homology to the phage P1 genome: implications for the evolution and spread of DNA restriction systems

Eco R124I, Eco DXXI and Eco prrI are the known members of the type IC family of DNA restriction and modification systems. The first three are carried on large, conjugative plasmids, while Eco prrI is chromosomally encoded. The enzymes are coded by three genes, hsdR , hsdM and hsdS . Analysis of the DNA sequences upstream and downstream of the type IC hsd loci shows that all are highly homologous to each other and also to sequences present in the bacteriophage P1 genome. The upstream sequences include functional phd and doc genes, which encode an addiction system that stabilizes the P1 prophage state, and extend to and beyond pac , the site at which phage DNA packaging begins. Downstream of the hsd loci, P1 DNA sequences begin at exactly the same place for all of the systems. For Eco DXXI and Eco prrI the P1 homology extends for thousands of base pairs while for Eco R124I an IS 1 insertion and an associated deletion have removed most of the P1-homologous sequences. The significance of these results for the evolution of DNA restriction and modification systems is discussed.     

Effects of static and fluctuating airway pressure on intact pulmonary circulation

The direct effects on the pulmonary circulation of static and fluctuation airway pressure were compared in intact close-chest infant lambs with reactive pulmonary vasculature under alpha-chloralose anesthesia. A preparation developed to permit independent ventilation of right and left lungs and independent measurement of right and left lung blood flow was employed to separate direct from indirect effects of unilateral airway pressure changes on pulmonary vascular resistance (PVR). Both static and fluctuating unilateral airway pressure interventions directly elevated ipsilateral PVR. For purposes of comparison mean alveolar pressure (PA) was estimated for both static and fluctuating trials. Fluctuating interventions increased PVR more than did static trials at comparable levels of PA. Substantially less PA was needed to double ipsilateral PVR by fluctuating than by static interventions (16 vs. 26 mmHg, respectively). These data indicate that, in the intact animal with reactive pulmonary vasculature, both PA and the waveform of airway pressure applied can influence PVR.     

MSI2通过下调circRNA_001214促进急性髓系白血病细胞HL60生长

Musashi-2（MSI2）是一种RNA结合蛋白质,对维持造血干细胞功能具有重要作用。研究表明,MSI2高表达能促进急性髓系白血病（acute myelocytic leukemia, AML）进展,但其作用机制尚不明确。本研究稳定沉默HL60细胞MSI2后,第1、2、3、4 d对照组的相对细胞生长率分别为1.931 ± 0.027、3.070 ± 0.073、4.017 ± 0.092和4.215 ± 0.246;敲减组分别为1.927 ± 0.035、2.564 ± 0.090、2.825 ± 0.097和3.223 ± 0.182,两组相比具有统计学差异,P<0.001;细胞凋亡明显增加(7.967% ± 0.698% vs 3.400% ± 0.322%., P<0.01);G₀/G₁期细胞比例明显增高（67.430% ± 4.390% vs. 50.360% ± 2.160%, P<0.01）;NUMB蛋白明显上调,LEF1明显下降。环状RNA（circular RNA, circRNA）芯片筛选和荧光定量PCR验证显示,MSI2沉默组circRNA_001214表达水平是对照组3.48倍。这一结果也在NALM6细胞得到证实。进一步用生物信息学分析,显示circRNA_001214最可能与miR-1273a、miR-1273e和miR 5095结合,进而影响参与细胞凋亡相关基因（CYCS、AKT1、BAX、TNFRSF10A、TNFRSF10D）、Wnt信号基因（WNT4、WNT2B、WNT7B、 DKK2、SFRP1、CSNKE1和LEF1）以及参与细胞代谢相关基因（RPE, PGAM4, PGAM1, TAT, CBS、RPE、SUCLG2、PGAM4、PGAM1和 IDNK）。总而言之,MSI2可能通过干扰circRNA_001214生成,减少靶miRNA对凋亡、Wnt信号及细胞代谢相关基因表达的影响,促进细胞生长。     

城市生态系统的模拟方法：灵敏度模型及其改进

评估城市生态系统的持续发展能力,探讨其持续发展对策是一个复杂的动态问题,需要运用动态的模拟方法进行。由德国著名生态控制论专家Ｆ．Ｖｅｓｔｅｒ和Ａ．Ｖ．Ｈｅｓｌｅｒ教授提出的“灵敏度模型”方法,将系统科学思想、生态控制论方法及城市规划融为一体,解释、模拟、评价和规划城市复杂的系统关系,是模拟城市生态系统很好的方法。本文对该方法进行了改进。改进后的“灵敏度模型”为评价城市持续发展能力、探讨其持续发展对策提供了新的思路。     

慢性心功能不全大鼠心脏和血淋巴细胞β-肾上腺素受体的改变

在主动脉与肾动脉缩窄造成的慢性心功能不全大鼠,血浆儿茶酚胺浓度增高;心脏β-肾上腺素受体(β-AR)数量增加,其中β_1-AR及其mRNA增加,而β_2-AR及其mRNA不变;左心房异丙基肾上腺素(ISO)浓度-收缩效应曲线右移;而心肌ISO浓度-cAMP蓄积曲线无显著改变;血淋巴细胞β-AR数量显著减少.结果提示心功能不全时心脏β_1-AR数量增多,但其介导的正性变力效应反而降低,在cAMP生成以后的信号转导过程或心肌收缩成分功能存在障碍,而血淋巴细胞β-AR的改变与心脏β-AR的功能改变平行.     

Participation of splenic vessels in blood supply to the pancreas (experimental-mathematical study)]

In 60 objects the participation of splenic vessels in human pancreas blood supply was studied roentgeno-angiographically and by means of anatomical preparation. Morphometrical data obtained were treated by computers "Minsk-22" and "M-220-M" to calculate main statistic values and their correlations. Some recommendations of applied importance for pancreas surgery were suggested. Maximal and minimal dimensions of the pancreas segments, which can be used for grafting with the following blood supply restoration in the transplant at the expense of the splenic vessels only, were represented.     

Stretch increases inositol trisphosphate and inositol tetrakisphosphate in cultured pulmonary vascular smooth muscle cells.

There are no reports of the effect of stretch on inositol phosphates in smooth muscle. Phosphoinositide and inositol phosphate metabolism was studied in cultured rat vascular smooth muscle cells subjected to stretching. The masses of inositol trisphosphate and tetrakisphosphate increased (+34 +/- 7% and +58 +/- 12%, respectively; p less than 0.001) after 25 s of a single 20% stretch and had returned to control levels by 45 s; phosphatidylinositol, phosphatidylinositol phosphate and bisphosphate did not change. Repetitive stretch did not alter the masses of any of the compounds. A single stretch also increased 45Ca2+ efflux (+52 +/- 5%, p less than 0.01). These data suggest that stretch of cultured vascular smooth muscle can elicit a rapid, short-lived increase in inositol phosphates, which may subsequently affect Ca2+.     

FXR在胃粘膜肠化生及胃癌中的表达及其意义研究

目的:研究FXR在胃炎,胃粘膜肠化生及胃癌组织中的表达,分析其在胃癌发生中的意义。方法:采用免疫组化方法检测FXR在55例胃炎组织,61例胃黏膜肠化生组织及61例胃癌组织中的表达,利用统计学方法 SPSS17.0软件分析其在三种组织中的表达变化,结合文献回顾,分析FXR在胃癌发生中的意义。结果:FXR在胃黏膜肠化生中的表达明显高于胃炎组织(P0.05),而在胃癌组织中,FXR的表达显著低于胃粘膜肠化生组织(P0.05)。结论:FXR是一个潜在的胃癌发生生物标记物,其具体机制有待于进一步探索。