Repression of FLOWERING LOCUS C and FLOWERING LOCUS T by the Arabidopsis Polycomb Repressive Complex 2 Components

Polycomb group (PcG) proteins are evolutionarily conserved in animals and plants, and play critical roles in the regulation of developmental gene expression. Here we show that the Arabidopsis Polycomb repressive complex 2 (PRC2) subunits CURLY LEAF (CLF), EMBRYONIC FLOWER 2 (EMF2) and FERTILIZATION INDEPENDENT ENDOSPERM (FIE) repress the expression of FLOWERING LOCUS C (FLC), a central repressor of the floral transition in Arabidopsis and FLC relatives. In addition, CLF directly interacts with and mediates the deposition of repressive histone H3 lysine 27 trimethylation (H3K27me3) into FLC and FLC relatives, which suppresses active histone H3 lysine 4 trimethylation (H3K4me3) in these loci. Furthermore, we show that during vegetative development CLF and FIE strongly repress the expression of FLOWERING LOCUS T (FT), a key flowering-time integrator, and that CLF also directly interacts with and mediates the deposition of H3K27me3 into FT chromatin. Our results suggest that PRC2-like complexes containing CLF, EMF2 and FIE, directly interact with and deposit into FT, FLC and FLC relatives repressive trimethyl H3K27 leading to the suppression of active H3K4me3 in these loci, and thus repress the expression of these flowering genes. Given the central roles of FLC and FT in flowering-time regulation in Arabidopsis, these findings suggest that the CLF-containing PRC2-like complexes play a significant role in control of flowering in Arabidopsis.     

腔内超声探头在甲状腺介入性超声中的应用价值

目的探讨腔内（阴道）超声探头在甲状腺介入性超声中的应用价值。方法对16例患者分别进行甲状腺局部注射药物、组织活检及囊肿介入性治疗,均使用腔内超声探头实时引导,未用穿刺架。结果所有操作均顺利完成,甲状腺和穿刺针都能清晰显像,术中疼痛较轻,无其余不适,术后均未见出血、颈部不适等不良反应。结论腔内超声探头具有体积小、频率高、视野宽、操作灵活、工作效率高的优点,非常适合于引导甲状腺的介入性操作,值得推广应用。     

3例肝动脉瘤破裂大出血病人的临床观察和护理

肝动脉瘤是一种少见的疾病,肝动脉瘤破裂大出血,常引起低血容量休克,如不及时抢救或抢救不当常危及生命,死亡率高达60%~70%[1]。肝内动脉瘤破裂胆道大出血手术病死率高达35%~50%[2]。因此,护理人员必须积极主动配合医生进行抢救。2006年我院收治肝内动脉瘤破裂大出血3例,采用肝动脉栓塞治疗,无一例死亡,获得较好的治疗效果。现将其抢救和护理介绍如下。1病例介绍[例1]病人,女,36例,因急性胆囊炎切除肿大胆囊,胆囊内有鲜血和血凝块,切开扩张的胆总管有鲜血和脓液涌出。探查胆道,未见结石和新生物,左胆管不断流出鲜血。结扎通向左肝的粗大迷走…     

苯磺酸氨氯地平治疗原发性高血压病26例超声心动图观察

本文利用超声心动图对新一代钙拮抗剂苯磺酸氨氯地平（ＡｍｌｏｄｉｐｉｎｅＢｅｓｙｌａｔｅ）治疗２６例Ⅰ～Ⅱ期高血压病前后的心脏功能及总外周阻力进行监测，发现此药在降压的同时，还具有较好的降低总外周阻力，减轻心肌重量，增加心输出量及射血分数，对心脏有一定的保护作用，为临床的治疗工作提供帮助。     

建立社区护理服务中心的构想

本文就建立社区护理服务中心的领导体制、服务队伍、服务模式等主要问题进行了初探，提出了相应的可行性构想。     

99mTc-sestamibi can improve the inferior attenuation of TL-201 myocardial spect imaging

Tl-201 myocardial scintigraphy (Tl study) tends to be attenuated by soft tissues (such as the diaphragm) due to its low energy emission. 99mTc-sestamibi (2-methoxy isobutyl isonitrile) is a relatively new agent with a higher energy emission and this characteristic accounts for the higher quality of 99mTc-sestamibi images. The purpose of this study is to evaluate the ability of 99mTc-sestamibi in alleviating the inferior attenuation of Tl studies. 99mTc-sestamibi SPECT myocardial scintigraphy was performed on 13 patients with inferior wall perfusion defects as determined by Tl study (but with normal coronary artery as evidenced by cardiac catheterization). All patients underwent Tl SPECT study using a standard procedure. Same-day protocol (rest-stress sequence) was used for 99mTc-sestamibi SPECT imaging. All images were analyzed by two independent observers. The results of our study reveal that 99mTc-sestamibi produced better images. The inferior wall perfusion defects in the Tl study were noted in one case only (l/13)in the 99mTc-sestamibi study. Our study suggests that 99mTc-sestamibi can remarkably reduce the inferior attenuation of Tl study.     

压敏胶片法在记忆生物力学实验中的新应用

目的:寻求记忆生物力学实验的新途径,探讨压敏胶片的生物力学特性及其在记忆生物力学实验中的应用。方法:利用生物力学实验装置,对待测试压敏胶片施加不同压力,得到不同颜色,分析比较颜色的灰度值,找出应力与颜色灰度值之间的关系。结果:对所得20组实验结果进行分析得到应力与颜色灰度值之间的关系,同时采用曲线拟和及最小二乘法得出应力与灰度值的对应关系式:yi=83.38816xi2-39244.89748xi+5199277.493。结论:压敏胶片法能够将动态的压力转化成静态的颜色灰度,在记忆生物力学实验中,选择合适的压敏胶片及工作环境,压敏胶片法将不失为一种较为理想的新方法。     

激素性股骨头坏死的细胞学变化

目的:观察长期大剂量使用糖皮质激素后兔股骨头组织细胞超微结构的变化,以及激素性股骨头缺血坏死的原因。方法:实验于2002-03/2003-06在西安交通大学第二医院骨病研究所完成。健康雄性日本白兔18只,随机分为两组,实验组为12只,皮下注射醋酸氢化泼尼松8mg/kg,1次/周。对照组6只,皮下注射生理盐水0.32mL/kg,1次/。取股骨头组织苏木精-伊红染色,苏丹Ⅲ染色,周光镜下计量空缺骨陷窝数和脂肪分布。用透射电子显微镜观察股骨头各系细胞超微结构的改变。结果:实验纳入兔18只,实验过程中,实验组死亡2只,进入结果分析16只。①光镜下两组兔股骨头空缺骨陷窝量的改变:实验组第4,8,12周股骨头软骨下区的皮质下骨小梁内空缺骨陷窝较对照组增多犤21.0±2.6)%比(12.0±1.8)%,(24.0±1.8)%比(12.0±1.3)%,(36.0±1.5)%(比(13.0±2.1)%,P<0.01犦8周和12周即可见到小片块状缺失骨;第细胞的区域。②光镜下两组之间股骨头脂肪细胞的改变:实验第8,12周实验组兔股骨头内脂肪细胞明显增大,骨陷窝内有被苏丹Ⅲ染成桔黄色的脂肪沉积,两组间均未见有脂肪栓子。两组间股骨头脂肪细胞大小变化统计学上有显著性意义。③电子显微镜观察两组股骨头超微结构变化:股骨头各系细胞早期(轻者)胞浆和胞核内出现脂质堆积,晚期成骨细胞核膜碎裂染色质溶解,血管内皮细胞胞浆肿胀出现脂滴,毛细血管壁肿胀,质膜结构不完整,可见到明显的裂隙。脂肪细胞核内可见脂滴。小静脉常被异常肥大的脂肪细胞压迫,使管腔骤然变窄。结论:长期大剂量使用糖皮质激素可导致股骨头各系细胞慢性缺血缺氧引起脂肪变性,晚期发生细胞坏死。     

Reversibility of severe metabolic stress in stored platelets after in vitro plasma rescue or in vivo transfusion: restoration of secretory function and maintenance of platelet survival

BACKGROUND: Determining reversible aspects of the platelet storage lesion may result in improved function and survival of transfused platelets. STUDY DESIGN AND METHODS: Using a model of high-dose (apheresis-derived) platelet concentrates (PC), functional changes imposed by transient adverse metabolic conditions (pH < 6.0 for 1-2 hr) that could be reversed by autologous plasma rescue followed by standard platelet storage were investigated. Whole-blood-derived PCs were transfused into a small number of normal volunteers to determine platelet recovery and survival. RESULTS: Without rescue, high-dose PCs developed severe in vitro functional derangements at the time of the pH nadir including 1) loss of resting morphology; 2) complete abrogation of osmotic recovery and platelet aggregation and glycoprotein IIb/IIIa up-regulation to agonist; and 3) decreased alpha-granule release. By contrast, spontaneous and agonist-induced binding of annexin V were unaffected by adverse metabolic conditions. Plasma rescue to an optimal pH improved morphology scores, stabilized osmotic recovery, and completely restored platelet secretory responses, as measured by aggregation, glycoprotein IIb/IIIa up-regulation, and alpha-granule release. In a limited number of studies, plasma rescue was accompanied by preserved in vivo platelet recovery and survival after autologous transfusion after 5 days of storage. CONCLUSION: Transient derangement of platelet metabolism, which does not increase membrane phosphatidylserine exposure, causes in vitro functional abnormalities that are fully reversed or stabilized by metabolic rescue. Preliminary data suggest that such rescued platelets may have normal posttransfusion recovery and survival.     

Altered spinal arachidonic acid turnover after peripheral nerve injury regulates regional glutamate concentration and neuropathic pain behaviors in rats

Spinal glutamate transporters (GT) have been implicated in the mechanisms of neuropathic pain; however, how spinal GT uptake activity is regulated remains unclear. Here we show that alteration of spinal arachidonic acid (AA) turnover after peripheral nerve injury regulated regional GT uptake activity and glutamate homeostasis. Chronic constriction nerve injury (CCI) in rats significantly reduced spinal GT uptake activity ((3)H-glutamate uptake) with an associated increase in extracellular AA and glutamate concentration from spinal microdialysates on postoperative day 8. AACOCF3 (a cytosolic phospholipase A2 inhibitor, 30mug) given intrathecally twice a day for postoperative day 1-7 reversed this CCI-induced spinal AA production, prevented the reduced spinal GT uptake activity and increased extracellular glutamate concentration. Conversely, alteration of spinal AA metabolism by diclofenac (a cyclooxygenase 1/2 inhibitor, 200mug) further reduced spinal GT uptake activity and increased extracellular glutamate concentration in CCI rats. GT uptake activity was also attenuated when AA (10 or 100nM) was directly added into spinal samples of na?ve rats in an in vitro(3)H-glutamate uptake assay, indicating a direct inhibitory effect of AA on GT uptake activity. Consistent with these findings, AACOCF3 reduced the development of both thermal hyperalgesia and mechanical allodynia, whereas diclofenac exacerbated thermal hyperalgesia, in CCI rats. Thus, spinal AA turnover may serve as a regulator in CCI-induced changes in regional GT uptake activity, glutamate homeostasis, and neuropathic pain behaviors. These data suggest that regulating spinal AA turnover may be a useful approach to improving the clinical management of neuropathic pain.