Nucleotide excision repair by dual incisions in plants

Plants use light for photosynthesis and for various signaling purposes. The UV wavelengths in sunlight also introduce DNA damage in the form of cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts [(6-4)PPs] that must be repaired for the survival of the plant. Genome sequencing has revealed the presence of genes for both CPD and (6-4)PP photolyases, as well as genes for nucleotide excision repair in plants, such as Arabidopsis and rice. Plant photolyases have been purified, characterized, and have been shown to play an important role in plant survival. In contrast, even though nucleotide excision repair gene homologs have been found in plants, the mechanism of nucleotide excision repair has not been investigated. Here we used the in vivo excision repair assay developed in our laboratory to demonstrate that Arabidopsis removes CPDs and (6-4)PPs by a dual-incision mechanism that is essentially identical to the mechanism of dual incisions in humans and other eukaryotes, in which oligonucleotides with a mean length of 26–27 nucleotides are removed by incising ∼20 phosphodiester bonds 5′ and 5 phosphodiester bonds 3′ to the photoproduct.Plants and other organisms that depend on photosynthesis are, by necessity, exposed to more sunlight than other organisms that are chemotrophs or heterotrophs. Hence, plants are expected to receive more exposure to UV wavelengths of light than other organisms. The genotoxic effects of UV are somewhat mitigated by the reflection of UV by the waxy leaf surface and absorbance of UV by the intracellular pigments that are present at high concentration in plant cells, including carotenoids and flavonoids. Nevertheless, plants still receive considerable amounts of DNA-damaging UV radiation and therefore must have the means to cope with the damage to ensure their survival. Indeed, DNA sequencing has revealed that plant genomes contain genes that are homologous to the genes of all major DNA repair pathways, including photoreactivation, nucleotide excision repair, base excision repair, and recombination/double-strand break repair (1–6).However, biochemical studies of these DNA repair mechanisms have been limited. Of significance, Arabidopsis photolyases have been expressed in heterologous systems, purified, and characterized (7–9). Similarly, some of the enzymes of the base excision repair and recombination/double-strand break repair systems have been studied. In contrast, there have been no mechanistic studies on plant nucleotide excision repair, although it is known that plants can remove cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts [(6-4)PPs] in a photolyase-independent manner (6, 10, 11), presumably by nucleotide excision repair. Here, we have used an Arabidopsis cell line and the in vivo excision assay recently developed in our laboratory (12–14) to demonstrate that Arabidopsis removes these photoproducts by dual incisions in a manner that is virtually identical to human nucleotide excision repair.     

Influence of experience on procedure steps,safety, and functional results in edge to edge mitral valve repair—a single center study

Objectives: We sought to determine the effects of experience on the Mitraclip^® procedure steps as well as procedure safety and functional results. Background: MR has proven deleterious in heart failure. Mitraclip^® therapy evolved an important option in patients with severely reduced left ventricular function (LVEF). Methods: Between 2011 and 2016, 126 consecutive patients were grouped in three groups and investigated in a prospective observational study. We evaluated the duration of procedural steps, safety endpoints, and functional results. Results: The median logistic EuroScore was 32% (7–40%). Ninety‐five percent of patients were in NYHA‐stage ≥III and 51% had a LVEF <30%. Groups were homogeneous as to their baseline NYHA status and right heart catheterization data. Echocardiography data are comparable, albeit with a decreasing effective regurgitant orifice area (0.44 ± 0.21 group I vs. 0.34 ± 0.22 group III, P = 0.02). Frailty was less frequent and baseline 6 min walking test results improved from group I to group III. Duration of a first clip placement decreased from 106 ± 50 to 50 ± 21 min (P < 0.001). Total procedure time decreased from 221 ± 70 to 144 ± 68 (P < 0.001). The number of clips implanted increased from 66 to 79 (P = 0.02). MitraClip^® implantation was effective in either group but the combined safety endpoint was reached less frequent in group III (P = 0.01). There was no difference in MACCE rate, 30 day‐ or intrahospital‐mortality between groups. Conclusion: Safety and duration of procedure steps improved substantially with experience. MR reduction was sustained from the beginning without further improvement. Patient selection is a key factor for success. © 2016 Wiley Periodicals, Inc.     

覆膜支架治疗37例Stanford B型胸主动脉夹层的疗效分析

目的:分析覆膜支架腔内修复治疗Stanford B型胸主动脉夹层的临床疗效。方法:对2015年1月至2016年12月收治的37例因Stanford B型胸主动脉夹层行覆膜支架腔内修复术患者的病历资料进行回顾性分析,其中男性29例,女性8例。术前诊断依据临床表现及CT血管造影(CTA),术中造影再次评估病变部位及解剖位置,切开股动脉,行覆膜内支架置入,封堵原发破口,手术成功后再次造影检查。结果:37例患者共置入支架37枚,全部获得成功。术中造影见少量内漏4例,3例经支架近端球囊扩张后内漏消失,1例无需特殊处理。患者临床症状均明显改善,降主动脉及腹主动脉真腔明显扩大。结论:采用覆膜支架腔内修复术治疗Stanford B型胸主动脉夹层安全、创伤小、恢复快,临床效果显著。     

非小细胞肺癌组织中表皮生长因子受体基因突变与ERCC1和RRM1mRNA表达的关系

目的探讨非小细胞肺癌（NSCLC）组织中人表皮生长因子受体（EGFR）基因突变与切除修复交叉互补蛋白1（ERCC1）和核苷酸还原酶亚单位M1（RRM1）mRNA表达的关系。方法应用实时荧光定量PCR方法检测257例NSCLC组织中EGFR基因突变、ERCC1和RRM1mRNA的表达。结果NSCLC组织中EGFR基因突变率占49．03％（126／257）,在女性和不吸烟患者中较高（P〈0．05）;ERCC1mRNA高表达占47．47％（122／257）,RRM1mRNA高表达占61．87％（159／257）。与未检测到EGFR基因突变的NSCLC患者比较,EGFR基因突变中ERCC1mRNA低表达者多见（P〈0．05）;NSCLC组织中,EGFR基因突变与RRM1mRNA表达水平无关（P〉0．05）;ERCC1mRNA表达水平与RRM1mRNA表达水平无关（P〈0．05）。结论NSCLC组织中EGFR基因突变患者ERCC1倾向低表达,可能受益于以铂类药物为基础的化疗。     

舒胃汤对功能性消化不良大鼠Cx43蛋白的分布及Cajal间质细胞的修复与再生的影响

[目的]观察舒胃汤对功能性消化不良（FD）肝郁脾虚型大鼠Cx43蛋白的分布及Cajal间质细胞的修复与再生的影响,探讨舒胃汤治疗FD的机制.[方法]将72只大鼠随机分为对照组、模型组、舒胃汤低剂量组（舒低组）、舒胃汤中剂量组（舒中组）、舒胃汤高剂量组（舒高组）和莫沙比利组（西药组）,每组各12只.舒低组、舒中组、舒高组分别给予舒胃汤0.767 g/ml、1.534 g/ml、3.068 g/ml,西药组予莫沙必利1.37 mg/kg.采用复合病因造模（慢性束缚应激十过度疲劳十饮食失节）,造成FD肝郁脾虚证大鼠模型.造模后第3天各组给予相应药液,对照组和模型组每日予以蒸馏水（10ml/kg）,均为1次/d,持续14 d.第15天处死取胃窦组织和小肠组织做免疫组织化学和荧光双染色观察Cx43蛋白的表达和ICC及神经纤维的形态.[结果]与对照组比较,模型组胃窦组织和小肠组织中Cx43蛋白阳性表达明显下降（P＜0.01）;与模型组比较,舒高组、舒中组和西药组胃窦组织和小肠组织中Cx43蛋白阳性表达明显升高（P＜0.01）;与对照组比较,模型组ICC超微结构损伤明显,胆碱能神经-ICC-SMC网络结构紊乱,ICC和神经纤维数目减少（P＜0.01）,荧光强度明显减弱（P＜0.01）;与模型组比较,舒高组、舒中组和西药组ICC超微结构较为正常完整,胆碱能神经-ICC-SMC网络基本完整,ICC和神经纤维数目明显增多（P＜0.01）,荧光强度明显加强（P＜0.01）.[结论]舒胃汤能够上调Cx43蛋白的表达,修复ICC和促进ICC的再生,增加神经纤维的数目,从而保持胆碱能神经-ICC-SMC网络结构的完整,恢复胃肠动力而有效治疗FD.     

胸腔镜手术治疗心包积液

目的 总结电视胸腔镜技术心包开窗术治疗心包积液的经验.方法 对12例进行胸腔镜下心包开窗和心包切除术治疗的心包积液病人临床资料进行回顾分析.结果 2例出现术中心律失常、急性心功能衰竭,术后胸引管保留时间3～14天,全部治愈,随访1年以上无复发.结论 电视胸腔镜下心包开窗术和心包切除治疗心包积液效果满意且创伤小、痛苦轻、恢复快.     

立芷雪与云南白药对宫颈环形电切术后创面脱痂止血效果的比较

目的 观察宫颈环形电切术后创面脱痂应用立芷雪和云南白药后的止血效果.方法 将患者随机分为两组,41例患者创面应用立芷雪1KU湿敷;41例患者创面应用云南白药1.0g湿敷,并作疗效的对比观察.结果 立芷雪组止血总有效率高于云南白药组,两组比较有显著差异(P＜0.05).结论 云南白药和立芷雪对于官颈环形电切术后创面脱痂止血均有效果,但立芷雪的效果优于云南白药.     

颅底中央区巨大表皮样囊肿显微外科治疗

目的:探讨颅底中央区巨大表皮样囊肿显微外科治疗的临床疗效.方法:回顾性分析显微外科手术治疗颅底中央区巨大表皮样囊肿36例的临床特点和手术体会.结果:36例颅底中央区巨大表皮样囊肿中,手术全切除32例,次全切除4例,颅神经损伤或症状加重13例,无手术死亡.结论:根据表皮样囊肿累及的部位,选择好手术入路和运用好显微外科技术可提高手术的全切率,降低并发症.