三维电解剖标测及单根环状标测电极指导下CPVA术治疗心房颤动

目的探讨在三维电解剖标测及单根环状标测电极指导下以环肺静脉口电隔离术（CPVA）为核心治疗心房颤动（房颤）的疗效。方法对32例房颤患者均在CARTO三维电解剖标测及单根环状标测电极指导下行CPVA,其中辅助行碎裂电位消融6例,上腔静脉消融术2例,三尖瓣峡部、二尖瓣峡部及冠状窦内消融各1例。结果26例阵发性房颤不再被诱发,6例慢性房颤中术中房颤终止2例、电复律转为窦性心律4例;手术操作时间（119±37）min,X线透视时间（25±12）min;随访（9±5）个月成功率为90.6%。均无手术并发症。结论三维电解剖标测及单根环状标测电极指导下以CPVA为核心,其他消融方法为辅的房颤消融策略安全有效,可提高消融成功率,缩短手术时间,减少并发症、复发。     

HBV感染者血清中HBVcccDNA、HBeAg及HBV DNA的关系

探讨HBV感染者血清HBVcccDNA与血清HBV DNA及HBeAg的关系。分别以PER分子信标技术和ELISA方法对非HBV相关肝炎、HBV健康携带者、急性乙型肝炎（AHB）、慢性乙型肝炎（CHB）、乙肝肝硬化、乙肝患者血清中HBVcccDNA HBV DNA含量及HBeAg进行了检测。HBVcccDNA仅见于HBV DNA阳性血清中；HBeAg阳性组的HBVcccDNA阳性率显著高于HBeAg阴性组（P〈0．05）；145例HBV DNA阳性患者中，HBVcccDNA阳性组HBVD—NA水平显著高于HBVcccDNA阴性组（P〈0．01）。血清HBVcccDNA可能是乙肝病毒在患者体内大量复制的血清标志。     

红霉素对人食管胃连接部的调节作用

人食管胃连接部(esophagogastric junction,EGJ)的结构及功能调节非常复杂.一般认为,人EGJ由食管下括约肌、远端食管以及胃底平滑肌形成的his角结构等共同形成,而人食管下括约肌又有别于大多数哺乳动物,由内层大弯侧套索纤维和小弯侧钩状纤维构成.红霉素(erythromycin)是一种大环内酯类抗生素,也是一种胃动素受体激动剂[1].本研究应用离体组织张力测定技术,探讨红霉素对人EGJ各类环行平滑肌张力的影响规律.     

The Structural and Functional Role of the B‐chain C‐terminal Arginine in the Relaxin‐3 Peptide Antagonist,R3(BΔ23‐27)R/I5

Relaxin‐3, a member of the insulin superfamily, is involved in regulating stress and feeding behavior. It is highly expressed in the brain and is the endogenous ligand for the receptor RXFP3. As relaxin‐3 also interacts with the relaxin receptor RXFP1, selective agonists and antagonists are crucial for studying the physiological function(s) of the relaxin‐3/RXFP3 pair. The analog R3(BΔ23‐27)R/I5, in which a C‐terminally truncated human relaxin‐3 (H3) B‐chain is combined with the INSL5 A‐chain, is a potent selective RXFP3 antagonist and has an Arg residue remaining on the B‐chain C‐terminus as a consequence of the recombinant protein production process. To investigate the role of this residue in the RXFP3 receptor binding and activation, the analogs R3(BΔ23‐27)R/I5 and R3(BΔ23‐27)R containing the B‐chain C‐terminal Arg as well as R3(BΔ23‐27)/I5 and R3(BΔ23‐27), both lacking the Arg, were chemically assembled and their secondary structure and receptor activity assessed. The peptides generally had a similar conformation but those with the extra Arg residue displayed a significantly increased affinity for the RXFP3. Interestingly, in contrast to R3(BΔ23‐27)R and R3(BΔ23‐27)R/I5, the peptide R3(BΔ23‐27) is a weak agonist. This suggests that the C‐terminal Arg, although increasing the affinity, alters the manner in which the peptide binds to the receptor and thereby prevents activation, giving R3(BΔ23‐27)R/I5 its potent antagonistic activity.     

Masthead,Volume 65, Issue 1

At sufficiently high Larmor frequencies, traveling electromagnetic waves along a magnet bore can be used for remote magnetic resonance excitation and detection, effectively using the bore as a waveguide. So far, this approach has relied only on the lowest waveguide modes and thus has not supported multiple‐channel operation for radiofrequency shimming and parallel imaging. In this work, this limitation is addressed by establishing a larger number of propagating modes and tapping their spatial field diversity with multiple waveguide ports. The number of available modes is increased by loading with dielectric inserts; the ports are implemented by stub and loop couplers at the end of a waveguide extension. The resulting traveling‐wave array, operated at 298 MHz in a 7T whole‐body magnet, is shown to enable radiofrequency shimming as well as parallel imaging with commonly used acceleration factors. The last part of the study concerns the amount of dielectric loading that is required. For the given Larmor frequency and bore dimensions, it is found that rather few water‐filled inserts, occupying ～5% of the bore cross‐section, are sufficient for effective parallel imaging. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Micropatterns of Non‐Circular Droplets of Nanostructured PS‐b‐PEO Copolymer by Solvent‐Assisted Wetting on a Chemically Periodic Surface

A method to fabricate micropatterns of non‐circular droplets of a self‐assembled block copolymer by solvent‐assisted wetting on chemically periodic surface is presented. The block copolymer is dewetted on a topographic pre‐pattern to form an array of microdroplets with a sphere‐capped shape and circular contact line. The droplets are then transferred onto a chemically periodic Au line pattern microcontact‐printed with two types of self‐assembled monolayers (SAMs). Solvent vapor application provides sufficient mobility to the block copolymer molecules to induce spreading of the transferred droplets, resulting in two types of non‐circular microdroplet growth. The growth behavior depends on the size of initial droplets relative to periodic line width and on the initial registries of as‐transferred droplets.     

Enteric circular muscle dysfunction in the cystic fibrosis mouse small intestine

Background Cystic fibrosis (CF) has multiple effects on the gastrointestinal system, including altered motility. The Cftr knockout mouse model of CF has impaired small intestinal transit but the mechanism is unknown. Methods Behaviour of circular smooth muscle was studied in an organ bath. Expression levels of prostaglandin (PG) degradative genes were measured by quantitative RT‐PCR, and PGE₂ levels were measured by enzyme immunoassay. Key Results Cystic fibrosis circular muscle activity was erratic and had variable frequency of contractions, as compared to WT. The CF tissue was non‐responsive to cholinergic stimulation or direct KCl depolarization. PGE₂ and PGF_2α are significantly elevated in the CF mouse small intestine, and we hypothesized these contribute to impaired smooth muscle activity. After inhibition of PG synthesis, the CF circular muscle exhibited greater cholinergic responsiveness, which was reversed by exogenous PGE₂. PGF_2α enhanced activity of CF tissue only after inhibition of PG synthesis. The enteric microbiota was implicated in PGE₂‐mediated dysmotility because broad spectrum antibiotic treated WT mice, which have slowed transit, exhibit impaired circular muscle activity. This was accompanied by decreased expression of PG degradative genes and increased intestinal PGE₂ levels. Furthermore, administration of oral laxative, which eradicates bacterial overgrowth and improves transit in CF mice, increased expression of PG degradative genes, decreased PGE₂ levels, and improved CF muscle activity. Conclusions & Inferences These results suggest that the enteric microbiota modulates PGE₂ levels in a complex manner, which affects enteric smooth muscle activity and contributes to slower small intestinal transit in CF.     

Structural and biosensor analyses of a synthetic biotinylated peptide probe for the isolation of adenomatous polyposis coli tumor suppressor protein complexes

Abstract: Large numbers of colon tumors stem from mutations in the gene coding for the production of the adenomatous polyposis coli (APC) tumor suppressor protein. This protein contains a coiled‐coil N‐terminal domain that is known to be responsible for homodimerization. Previous work by others has led to the design of a specific 54‐residue anti‐APC peptide (anti‐APCp1) that dimerizes preferentially with this domain. We have undertaken the chemical synthesis of a modified form of this peptide (anti‐APCp2) that bears a biotin moiety at its N‐terminus for use in subsequent ligand‐binding analysis studies. The peptide was subjected to comprehensive chemical characterization to confirm its purity. Secondary structural analysis by circular dichroism spectroscopy and Fourier transform infrared spectroscopy indicated that the peptide could assume a wide range of potential conformations, depending upon the precise microenvironment. Significantly, a stable α‐helical structure was generated when the solvent conditions supported intramolecular salt‐bridge formation along the helix barrel. The biotinylated anti‐APCp2 was immobilized onto a streptavidin sensor surface, in a specific orientation leaving all amino acids available to form a coiled structure. In one experiment, injection of colonic cell lysate extracts (LIM1215) onto a size‐exclusion column resulted in the isolation of a high molecular mass protein peak (> 600 kDa) that reacted specifically with the immobilized anti‐APCp2 on the biosensor surface. In another experiment, a high molecular mass protein (M_r > 250 kDa on SDS?PAGE) could be specifically immunoprecipitated from this peak using either the anti‐APCp2 peptide or an anti‐APC polyclonal antibody. This demonstrates the specific interaction between the anti‐APCp2 peptide and native APC and highlights the potential use of the former peptide in a multidimensional micropreparative chromatographic/biosensor/proteomic protocol for the purification of APC alone and APC complexed with different biopolymers in various cell lines, and stages of tumor development.