• 【双阑尾病例中的急性单阑尾炎: 一个罕见的发现。】 复制标题 收藏 收藏
    DOI:10.29271/jcpsp.2020.04.440 复制DOI
    作者列表:Akbaş A,Hacim NA,Daşiran F,Dagmura H,Daldal E
    BACKGROUND & AIMS: :Appendiceal duplication is an extremely rare entity in adulthood. It is usually diagnosed incidentally during laparotomy performed for another indication. Herein, we present a case of double appendicitis in a 31-year male who underwent laparotomy with a preliminary diagnosis of acute appendicitis. Two appendices attached via separate bases to a cecum were identified intraoperatively. One of them was thick-walled, partial 1 perforated from the apex region and the other one was normal looking. Both had their own radices. They were stuck together at their apical parts. Appendicectomy was performed for both of them. Due to the fact that appendicectomy is the most common abdominal surgery procedure, surgeons should always bear in mind this rare anomaly, in order to prevent complications. Key Words: Appendiceal duplication, Cecum, Anatomic variation.
    背景与目标: : 阑尾重复是成年期极为罕见的实体。通常在进行另一种适应症的剖腹手术时偶然诊断。在此,我们介绍了一名31岁男性的双阑尾炎病例,该患者接受了剖腹手术,并初步诊断为急性阑尾炎。术中确定了两个通过单独的基部附着在盲肠上的阑尾。其中一个是厚壁的,部分1从顶点区域穿孔,另一个是正常的。两者都有自己的radices。他们在顶端被粘在一起。对两者均进行了阑尾切除术。由于阑尾切除术是最常见的腹部手术,因此外科医生应始终牢记这种罕见的异常,以防止并发症。关键词: 阑尾重复,盲肠,解剖变异。
  • 【2 '-O,4'-C-乙烯核酸 (ENA) 的改进合成和含鸟苷ENA单元的双链体形成的热力学研究。】 复制标题 收藏 收藏
    DOI:10.1080/15257770.2019.1708389 复制DOI
    作者列表:Takagi-Sato M,Morita K,Onishi Y,Watahiki Y,Ishigaki T,Akita T,Tomita E,Kawakami J,Koizumi M
    BACKGROUND & AIMS: :Oligonucleotides containing 2'-O,4'-C-ethylene nucleic acids (ENA) have been proven highly effective for antisense therapeutics. 2'-O,4'-C-Ethyleneguanosine and its phosphoramidite were previously obtained from 3,5-di-O-benzy1-4-C-(p-tolulenesulfonyloxyethyl)-1,2-di-O-acetyl-α-D-erythropentofuranose by glycosylation, but with limited efficiency. Using 3,5-di-O-benzy1-4-C-(2-t-butyldiphenylsilyloxyethyl)-1,2-di-O-acetyl-α-D-erythropentofuranose as an alternative substrate, we developed several methods to obtain 2'-O,4'-C-ethyleneguanosine derivatives with much higher yields than previously reported. These methods were also applicable for the synthesis of 2'-O,4'-C-ethyleneadenosine and 2'-O,4'-C-ethylene-5-methyluridine derivatives. Moreover, we investigated the thermodynamic benefit of DNA strands containing 2'-O,4'-C-ethyleneguanosines during duplex formation with complementary RNA. Only a single modification by the nucleoside resulted in a 10-fold greater binding constant of the DNA/RNA duplex.
    背景与目标: : 含有2 '-O,4'-C-乙烯核酸 (ENA) 的寡核苷酸已被证明对反义治疗非常有效。2 '-O,4'-C-亚乙基鸟苷及其亚磷酰胺先前是通过糖基化从3,5-二-O-苄基1-4-c-(对甲苯磺酰氧基乙基)-1,2-di-O-acetyl-α-D-erythropentofuranose获得的,但效率有限。使用3,5-二-O-苄基1-4-c-(2-叔丁基二苯基甲硅烷基氧基乙基)-1,2-di-O-acetyl-α-D-erythropentofuranose作为替代底物,我们开发了几种方法来获得2 '-O,4'-C-乙基鸟苷衍生物,其收率远高于以前报道的。这些方法也适用于2 '-O,4'-C-乙烯腺苷和2 '-O,4'-C-ethylene-5-methyluridine衍生物的合成。此外,我们研究了含有2 '-O,4'-C-亚乙基鸟嘌呤的DNA链在互补RNA双链形成过程中的热力学益处。只有核苷的一次修饰才能使DNA/RNA双链体的结合常数提高10倍。
  • 【快速、灵敏的单管双链rt-pcr检测基孔肯雅热和登革热的特异性和鉴别诊断疾病。】 复制标题 收藏 收藏
    DOI:10.1016/j.jviromet.2013.07.029 复制DOI
    作者列表:Saha K,Firdaus R,Chakrabarti S,Sadhukhan PC
    BACKGROUND & AIMS: :Chikungunya and dengue, two arboviral infections are common in South-East Asia and their early clinical manifestations are very similar hence it is important to discriminate between them as early as possible for better clinical management. The aim of this study was to design a rapid, sensitive and specific method for the differential diagnosis of these two viruses simultaneously. A rapid one-tube duplex RT-PCR assay was developed that requires 110 min including RNA extraction, RT-PCR and agarose gel electrophoresis by using a novel Taq polymerase with high processivity. This one-tube duplex RT-PCR system with primers designed from the conserved regions of the genome allowed discrimination between the two viral groups. Bioinformatics analysis of the DNA sequences from PCR amplified products confirmed that this method was very specific and accurate. The time required for this duplex RT-PCR was comparable to the standard IgM capture ELISA method. This novel approach would help to diagnose specifically and accurately these two closely related arboviruses and enable early detection from blood. This method could be applied in resource limited settings, for surveillance in endemic regions or for routine epidemiological screening.
    背景与目标: : 基孔肯雅热和登革热,两种虫媒病毒感染在东南亚很常见,它们的早期临床表现非常相似,因此尽早区分它们以更好的临床管理很重要。这项研究的目的是设计一种快速,灵敏和特异的方法来同时鉴别诊断疾病这两种病毒。开发了一种需要110分钟的快速单管双链rt-pcr分析,包括RNA提取、rt-pcr和琼脂糖凝胶电泳,通过使用具有高加工性的新型Taq聚合酶。这种单管双链rt-pcr系统具有从基因组保守区域设计的引物,可以区分两个病毒组。对PCR扩增产物DNA序列的生物信息学分析证实,该方法非常特异性和准确性。这种双重rt-pcr所需的时间与标准IgM捕获ELISA方法相当。这种新颖的方法将有助于特异性和准确地诊断这两种密切相关的虫媒病毒,并能够从血液中早期发现。此方法可用于资源有限的环境,流行地区的监测或常规流行病学筛查。
  • 【通过血管造影或双重扫描识别主动脉和股腘动脉疾病的成本效益。】 复制标题 收藏 收藏
    DOI:10.1016/j.ejrad.2007.06.001 复制DOI
    作者列表:Coffi SB,Ubbink DT,Dijkgraaf MG,Reekers JA,Legemate DA
    BACKGROUND & AIMS: OBJECTIVES:Cost-effectiveness analysis of three diagnostic imaging strategies for the assessment of aortoiliac and femoropopliteal arteries in patients with peripheral arterial occlusive disease. The strategies were: angiography as the reference strategy, duplex scanning (DS) plus supplementary angiography (S1) and DS plus confirmative angiography (S2). DESIGN, MATERIALS AND METHODS:A decision model was built with sensitivity and specificity data from literature, supplemented with prospective hospital cost data in Euro (euro). The probability of correctly identifying the status of a lesion was taken as the primary outcome. We compared strategies by assessing the extra costs per additional correctly identified case. RESULTS:Assuming no false positive or false negative results, angiography is the most effective strategy if the prevalence of significant obstructive lesions in the aortoiliac and femoropopliteal tract exceeds 70%, or if the sensitivity of duplex scanning is lower than 83%. In case of lower prevalence, strategy S1 becomes equally or even more effective than angiography. At a prevalence of 75%, performing angiography costs euro 8443 per extra correctly identified case compared with strategy S1. CONCLUSIONS:In most situations angiography is more effective than diagnostic strategy S1. However, if society is unwilling to pay more than euro 8443 for knowing a patient's disease status, diagnostic strategy S1 is a cost-effective alternative to angiography, especially at lower prevalence values.
    背景与目标:
  • 【基本了解木质素的颜色区别以及在颜色依赖的利用中正确选择木质素。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijbiomac.2020.01.105 复制DOI
    作者列表:Zhang H,Fu S,Chen Y
    BACKGROUND & AIMS: :Lignin based materials and chemicals with outstanding sustainability have drawn increasingly attentions. However, the dark color of lignin limits the utilization in color-depended fields. In this work, the factors that influence the color of lignin were investigated and mechanisms were illustrated by GPC, NBO, 2D HSQC, XPS, SEM, and visible light spectrum. It is found that the condensed structures were mainly separated at higher pH due to its high molecular weight and low solubility. The condensation contributes to the conjugation and unsaturation, which resulted in the dark-color of the lignin precipitated at high pH value. The oxidation is not crucial for the color darkening of lignin in drying, it is the micro aggregation that dominantly determined the color degree. The concentration of chromophore was decreased owing to the decrease of bulk density (caused by the alleviation of aggregation), which endowed lignin with the bright seeing macroscopically. Notably, the selection of light-colored lignin needs to be individually considered regarding different use, since the dominating factors that influence the color at solid or solution are totally different. In summary, this work offers guidance for acquiring light-colored lignin and helps people select the light-colored lignin properly regarding utilizations.
    背景与目标: : 具有突出可持续性的木质素基材料和化学品越来越受到关注。但是,木质素的深色限制了在与颜色有关的领域中的利用率。在这项工作中,研究了影响木质素颜色的因素,并通过GPC,NBO,2D HSQC,XPS,SEM和可见光光谱说明了其机理。发现由于其高分子量和低溶解度,缩合结构主要在较高的pH下分离。冷凝会导致共轭和不饱和,从而导致木质素在高ph值下沉淀出深色。氧化对于干燥过程中木质素的颜色变暗不是至关重要的,微聚集主要决定了色度。发色团的浓度由于堆积密度的降低 (由于聚集的减轻而引起) 而降低,这使木质素在宏观上具有明亮的视觉效果。值得注意的是,由于影响固体或溶液颜色的主要因素完全不同,因此需要针对不同的用途单独考虑选择浅色木质素。总之,这项工作为获取浅色木质素提供了指导,并帮助人们在利用方面正确选择浅色木质素。
  • 【平行检测违反颜色恒定性。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.141505198 复制DOI
    作者列表:Foster DH,Nascimento SM,Amano K,Arend L,Linnell KJ,Nieves JL,Plet S,Foster JS
    BACKGROUND & AIMS: :The perceived colors of reflecting surfaces generally remain stable despite changes in the spectrum of the illuminating light. This color constancy can be measured operationally by asking observers to distinguish illuminant changes on a scene from changes in the reflecting properties of the surfaces comprising it. It is shown here that during fast illuminant changes, simultaneous changes in spectral reflectance of one or more surfaces in an array of other surfaces can be readily detected almost independent of the numbers of surfaces, suggesting a preattentive, spatially parallel process. This process, which is perfect over a spatial window delimited by the anatomical fovea, may form an early input to a multistage analysis of surface color, providing the visual system with information about a rapidly changing world in advance of the generation of a more elaborate and stable perceptual representation.
    背景与目标: : 尽管照明光的光谱发生变化,反射表面的感知颜色通常保持稳定。可以通过要求观察者将场景上的照明变化与包含该场景的表面的反射特性的变化区分开来操作地测量这种颜色恒定性。这里显示的是,在快速光源变化期间,几乎可以独立于表面的数量而容易地检测到其他表面阵列中一个或多个表面的光谱反射率的同时变化,这表明这是一种预先注意的,空间平行的过程。此过程在由解剖中央凹界定的空间窗口上是完美的,可以形成对表面颜色的多阶段分析的早期输入,从而在生成更精细的之前为视觉系统提供有关快速变化的世界的信息。和稳定的感知表示。
  • 【选定的问卷大小和颜色组合与邮寄调查回复率显着相关。】 复制标题 收藏 收藏
    DOI:10.1016/j.jclinepi.2007.01.006 复制DOI
    作者列表:Beebe TJ,Stoner SM,Anderson KJ,Williams AR
    BACKGROUND & AIMS: OBJECTIVE:To determine the degree to which mailed survey response rates, response times, and nonresponse bias are affected by questionnaire size and color. STUDY DESIGN AND SETTING:Questionnaires were mailed to a random sample of 2,000 Mayo Clinic patients in one of four size/color "test" groups. One thousand three hundred nine surveys were completed, approximately two-thirds in each group. RESULTS:A small (6 (1/8) x 8 (1/4) in) questionnaire booklet on white paper had a higher response rate (68.4%) than a similarly sized questionnaire on blue paper (62.3%). A large (8 (1/4) x 11 in) questionnaire on white paper had a 62.7% rate, whereas a large, blue questionnaire had a response rate of 68.6%. Median response times did not differ by questionnaire size/color. No evidence of differential nonresponse bias was observed across the four test groups. CONCLUSION:This study supports the use of a small/white questionnaire format advocated by the Total Design Method advanced by Don Dillman at Washington State University. We observed a favorable response rate for a large questionnaire printed on blue paper; however, if time and resources are limited, use of a small/white questionnaire appears preferable.
    背景与目标:
  • 【术中多普勒彩色血流图用于二尖瓣返流瓣膜修复的决策。100患者的技术和结果。】 复制标题 收藏 收藏
    DOI:10.1161/01.cir.81.2.556 复制DOI
    作者列表:Stewart WJ,Currie PJ,Salcedo EE,Lytle BW,Gill CC,Schiavone WA,Agler DA,Cosgrove DM
    BACKGROUND & AIMS: :Mitral valve repair provides substantial advantages over mitral valve replacement in patients with severe mitral regurgitation. However, because of the possibility of persistent regurgitation, an intraoperative technique is needed to provide an immediate and accurate assessment of the adequacy of the repair before closure of the chest. One hundred patients with pure mitral regurgitation were studied with intraoperative epicardial Doppler color flow mapping immediately before and after valve repair. Intraoperative assessment of the severity of mitral regurgitation showed good agreement with preoperative left ventriculography and with standard precordial Doppler echocardiography before and after surgery. Postrepair intraoperative Doppler studies showed satisfactory surgical results in 92 patients. Postrepair intraoperative Doppler studies in the remaining eight patients demonstrated unsatisfactory results: persistent significant regurgitation in four, systolic anterior motion of the mitral valve with dynamic left ventricular outflow tract obstruction in three, and a persistent flail leaflet in one. In six of the eight patients, further surgery was performed during the same thoracotomy. In two patients, the intraoperative postrepair Doppler findings of persistent regurgitation were confirmed on precordial Doppler studies within 5 days, and mitral reoperation was required. Intraoperative epicardial Doppler color flow mapping provided a "safety net" that ensured a successful outcome in all 100 patients by providing the surgeon with a direct means to assess the success of the operation and the need for further surgery.
    背景与目标: : 在严重二尖瓣反流患者中,二尖瓣修复比二尖瓣置换术具有明显优势。但是,由于存在持续返流的可能性,因此需要一种术中技术来在闭合胸部之前立即准确地评估修复的充分性。在瓣膜修复前后立即通过术中心外膜多普勒彩色血流图研究了一百例纯二尖瓣反流的患者。术中评估二尖瓣反流的严重程度与术前左心室造影和手术前后的标准心前区多普勒超声心动图吻合良好。对术中多普勒检查显示92例患者的手术效果令人满意。其余8例患者的术中多普勒检查显示结果不理想: 4例持续明显反流,3例二尖瓣收缩期前运动,动态左心室流出道梗阻,1例持续连枷小叶。在八名患者中的六名中,在相同的开胸手术中进行了进一步的手术。在两名患者中,在5天内通过心前区多普勒检查证实了术中对后多普勒检查的持续性反流,需要进行二尖瓣再次手术。术中心外膜多普勒彩色血流图提供了 “安全网”,通过为外科医生提供直接评估手术成功和进一步手术需求的直接手段,确保了所有100患者的成功结局。
  • 【[经颅彩色编码双工超声在监测神经危重症患者中的应用]。】 复制标题 收藏 收藏
    DOI:10.1016/s0210-5691(07)74858-1 复制DOI
    作者列表:Abadal JM,Llompart-Pou JA,Homar J,Pérez-Bárcena J,Ibáñez J
    BACKGROUND & AIMS: :Transcranial sonography is a common tool for monitoring neurocritical patients. Transcranial color-coded duplex ultrasonography enables hemodynamic and structural study of the cerebral parenchyma in these patients. Its advantages over conventional ultrasonography are evident and are derived from direct visualization of the vessel to be studied and appropriate adjustment of the sample volume and angle of insonation. The use of ultrasonographic contrast agents enables conclusive findings in practically 100% of cases and allows cerebral perfusion to be studied at the bedside using semiquantitative methods. This review aims to show the applications of transcranial color-coded duplex ultrasonography for monitoring neurocritical patients in intensive care units.
    背景与目标: : 经颅超声检查是监测神经危重症患者的常用工具。经颅彩色编码的双工超声检查可对这些患者的脑实质进行血流动力学和结构研究。与常规超声检查相比,它的优势是显而易见的,并且源于对要研究的血管的直接可视化以及对样品体积和声角的适当调整。使用超声造影剂可以在实际100% 的情况下得出结论,并允许使用半定量方法在床边研究脑灌注。这篇综述旨在展示经颅彩色编码双工超声在重症监护病房中监测神经危重患者的应用。
  • 【使用标准化彩色照片评估前睑缘炎的体征。】 复制标题 收藏 收藏
    DOI:10.1097/ICO.0b013e3182a02e0e 复制DOI
    作者列表:Bunya VY,Brainard DH,Daniel E,Massaro-Giordano M,Nyberg W,Windsor EA,Pearson DJ,Huang J,Maguire MG,Stone RA
    BACKGROUND & AIMS: PURPOSE:To describe a standardized technique for acquiring and viewing photographic images of eyelids, assess the reproducibility and validity of a grading protocol for signs of anterior blepharitis, and to explore whether the signs depend on the eyelid or the area of the eyelid assessed. METHODS:Subjects with anterior blepharitis ranging from none to severe were examined by ophthalmologists at clinical sites. Digital images of the eyelids of subjects were acquired using a protocol that allowed for the calibration of color and luminance. Three ophthalmologists at a centralized reading center applied a novel protocol for grading features of anterior blepharitis from the digital images viewed on color-calibrated monitors. The agreement among graders was assessed using percent agreement and weighted kappa statistics (Kw), and the correlation of photographic and clinical gradings was assessed using Spearman correlation coefficients. RESULTS:Agreement among graders was excellent (Kw > 0.80) on the number of eyelid margin vessels and was substantial (Kw between 0.61 and 0.80) for erythema, collarettes, number of engorged vessels, and number of lashes. Grading of the photographic images and the clinical assessments of erythema and lid debris were moderately correlated (r = 0.27-0.45). The grades for different features depended on whether the upper or lower eyelid, eyelid skin or lid margin, and central or lateral lid were assessed. CONCLUSIONS:The application of a protocol to obtain and display calibrated digital images of eyelids supports the standardized assessment of anterior blepharitis in clinical care and research studies.
    背景与目标:
  • 【经颅彩色编码的双工超声检查用于检测颈内动脉远端狭窄。】 复制标题 收藏 收藏
    DOI:10.3174/ajnr.A0789 复制DOI
    作者列表:Valaikiene J,Schuierer G,Ziemus B,Dietrich J,Bogdahn U,Schlachetzki F
    BACKGROUND & AIMS: BACKGROUND AND PURPOSE:Gradation of high-grade intracranial internal carotid artery (ICA) stenosis poses a challenge to noninvasive neurovascular imaging, which seems critical for angioplasty in the ICA segments C1 and C5. We investigated cutoff values of intracranial ICA stenosis for transcranial color-coded sonography (TCCS) and compared this method with the "gold standard," digital subtraction angiography (DSA). MATERIALS AND METHODS:Forty patients (mean age, 58.9 +/- 13.8 years) with intracranial ICA lesions were prospectively examined by using TCCS and DSA. Two standard TCCS coronal imaging planes were used to evaluate the intracranial ICA. In addition, a control group of 128 volunteers without cerebrovascular disease (mean age, 48.8 +/- 15.9 years) was investigated to establish standard velocity values. RESULTS:DSA confirmed 96 stenoses and 8 occlusions of the intracranial ICA in the study population. In 9% and 7% of cases, stenosis confined to the C1 or C5 segment was >50% and 70%, respectively. Receiver-operating curves demonstrated cutoff values for >70% stenosis in C1 when the peak systolic velocity (PSV) was >200 cm/s (specificity, 100%; sensitivity, 71%) or the C1/submandibular ICA index was >3 (specificity, 93%; sensitivity, 86%). CONCLUSIONS:TCCS is a reliable adjunctive method to detect and quantify significant stenosis of the intracranial ICA. The assessment of the C1/ICA index and peak systolic velocities maximizes the diagnostic accuracy of C1 stenosis to >70% when extracranial ICA stenosis coexists. Further studies need to be performed to compare the diagnostic accuracies of MR angiography and TCCS with that of DSA.
    背景与目标:
  • 【台湾2015年6月28日台塑彩色粉尘爆炸499名烧伤伤亡的分配经验。】 复制标题 收藏 收藏
    DOI:10.1016/j.burns.2016.10.008 复制DOI
    作者列表:Wang TH,Jhao WS,Yeh YH,Pu C
    BACKGROUND & AIMS: OBJECTIVE:To describe the experience of distributing 499 burn casualties of an unexpected event and determine whether patient transfer is associated with patient outcomes measured 2 weeks after the incident. METHODS:All 499 patients injured in the event were included. For the 138 patients transferred to other hospitals after primary distribution, we evaluated whether the transfers were associated with patient severity. Furthermore, we used multinomial logistic regression to investigate the association of patient transfer with patient outcomes after controlling for age, gender, total burn surface area (TBSA), final hospital level, wound infection, and patient pneumonia. RESULTS:We determined that on-site triage differed significantly from hospital triage (p<0.001). Furthermore, the secondary distribution enabled the transfer of a high number of patients to medical centers based on the availability of beds; however, such transfers were not associated with patient outcomes (p>0.05). Factors associated with patient outcomes were wound infection and TBSA (p<0.001). CONCLUSIONS:In case of inadequate burn centers, satisfactory patient outcomes can be achieved by the immediate treatment of patients, despite the treating hospitals being lower-level hospitals. Regardless of the hospital level, immediate treatment of burn patients is crucial to reducing mortality.
    背景与目标:
  • 【在正常人类胎儿的整个妊娠过程中,颜色M模式传播速度 (但与舒张早期流入速度之比却没有变化)。】 复制标题 收藏 收藏
    DOI:10.1002/uog.5303 复制DOI
    作者列表:Moon-Grady AJ,Taylor D,Bennett SH,Hornberger LK,Tacy TA
    BACKGROUND & AIMS: OBJECTIVES:Color M-mode propagation velocity (Vp) is a measure of diastolic function in adults and, when combined with early diastolic inflow velocity (E), the ratio E/Vp reflects ventricular filling pressure. Early detection of diastolic compromise may benefit fetal patients at risk for developing heart failure. The objectives of this study were to measure values for Vp and inflow peak E in a group of normal fetuses, to analyze age-dependent alterations in these measurements, and to evaluate the interobserver and intraobserver variability of the measurements. METHODS:Thirty-two normal fetuses at between 20 and 35 weeks' gestation underwent echocardiography. Color M-mode Vp was measured from the four-chamber view for the right (RV) and left (LV) ventricles, and mitral and tricuspid inflow velocities were determined by pulsed-wave Doppler ultrasound. The values obtained were compared with previously reported findings in adults. RESULTS:Adequate tracings were obtainable in 23 patients for the RV and 29 for the LV. Mean Vp values for the RV (15.3 +/- 3.2 cm/s) and LV (20.8 +/- 5.6 cm/s) were lower than normal adult values, and Vp values were significantly lower for the RV than the LV (P < 0.001). Applying Bazett's heart rate correction, values for RV (23.4 +/- 4.8 cm/s) and LV (31.9 +/- 8.7 cm/s) remained lower than normal adult values. There was a linear correlation of Vp with gestational age for the RV (R = 0.69, P < 0.001), and the ratio of E/Vp corrected for heart rate for the RV (1.51 +/- 0.26) remained constant throughout gestation. Interobserver bias was high but intraobserver bias low, at 19 and 1.1%, respectively. CONCLUSIONS:Vp is lower in fetal than in adult life. Vp for the RV changes in a manner indicative of improving diastolic function throughout normal gestation, providing insight into the alterations in diastolic function with gestation that contribute to increases in cardiac output. The use of Vp to assess diastolic function disturbance in fetuses is feasible, but high interobserver variability is problematic.
    背景与目标:
  • 【果蝇髓质中的色觉回路。】 复制标题 收藏 收藏
    DOI:10.1016/j.cub.2008.02.075 复制DOI
    作者列表:Morante J,Desplan C
    BACKGROUND & AIMS: BACKGROUND:Color vision requires comparison between photoreceptors that are sensitive to different wavelengths of light. In Drosophila, this is achieved by the inner photoreceptors (R7 and R8) that contain different rhodopsins. Two types of comparisons can occur in fly color vision: between the R7 (UV sensitive) and R8 (blue- or green sensitive) photoreceptor cells within one ommatidium (unit eye) or between different ommatidia that contain spectrally distinct inner photoreceptors. Photoreceptors project to the optic lobes: R1-R6, which are involved in motion detection, project to the lamina, whereas R7 and R8 reach deeper in the medulla. This paper analyzes the neural network underlying color vision into the medulla. RESULTS:We reconstruct the neural network in the medulla, focusing on neurons likely to be involved in processing color vision. We identify the full complement of neurons in the medulla, including second-order neurons that contact both R7 and R8 from a single ommatidium, or contact R7 and/or R8 from different ommatidia. We also examine third-order neurons and local neurons that likely modulate information from second-order neurons. Finally, we present highly specific tools that will allow us to functionally manipulate the network and test both activity and behavior. CONCLUSIONS:This precise characterization of the medulla circuitry will allow us to understand how color vision is processed in the optic lobe of Drosophila, providing a paradigm for more complex systems in vertebrates.
    背景与目标:
  • 【用于促进酵母U4/U6 RNA双链体退绕的多步模型。】 复制标题 收藏 收藏
    DOI:10.1093/nar/gkw686 复制DOI
    作者列表:Rodgers ML,Didychuk AL,Butcher SE,Brow DA,Hoskins AA
    BACKGROUND & AIMS: :The small nuclear RNA (snRNA) components of the spliceosome undergo many conformational rearrangements during its assembly, catalytic activation and disassembly. The U4 and U6 snRNAs are incorporated into the spliceosome as a base-paired complex within the U4/U6.U5 small nuclear ribonucleoprotein (tri-snRNP). U4 and U6 are then unwound in order for U6 to pair with U2 to form the spliceosome's active site. After splicing, U2/U6 is unwound and U6 annealed to U4 to reassemble the tri-snRNP. U6 rearrangements are crucial for spliceosome formation but are poorly understood. We have used single-molecule Förster resonance energy transfer and unwinding assays to identify interactions that promote U4/U6 unwinding and have studied their impact in yeast. We find that U4/U6 is efficiently unwound using DNA oligonucleotides by coupling unwinding of U4/U6 stem II with strand invasion of stem I. Unwinding is stimulated by the U6 telestem, which transiently forms in the intact U4/U6 RNA complex. Stabilization of the telestem in vivo results in accumulation of U4/U6 di-snRNP and impairs yeast growth. Our data reveal conserved mechanisms for U4/U6 unwinding and indicate telestem dynamics are critical for tri-snRNP assembly and stability.
    背景与目标: : 剪接体的小核RNA (snRNA) 成分在其组装,催化活化和拆卸过程中会经历许多构象重排。U4和U6 snrna作为U4/U6.U5小核核糖核蛋白 (tri-snRNP) 内的碱基配对复合物掺入剪接体中。然后将U4和U6展开,以便U6与U2配对以形成剪接体的活性位点。拼接后,将U2/U6展开,并将U6退火至U4以重新组装tri-snRNP。U6重排对于剪接体的形成至关重要,但知之甚少。我们已经使用单分子f ö rster共振能量转移和退绕测定法来鉴定促进U4/U6退绕的相互作用,并研究了它们在酵母中的影响。我们发现,通过将U4/U6茎II的退绕与茎I的链侵袭偶联,使用DNA寡核苷酸有效地解开了U4/U6。U6远干刺激解旋,该远干在完整的U4/U6 RNA复合物中瞬时形成。体内远端的稳定会导致U4/U6 di-snRNP的积累并损害酵母的生长。我们的数据揭示了U4/U6退绕的保守机制,并表明远程动力学对于tri-snRNP组装和稳定性至关重要。

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