多层螺旋CT低剂量扫描在小儿胸部的应用探讨

目的:评价小儿胸部多层螺旋CT低剂量与常规剂量扫描的图像质量,探讨低剂量扫描在小儿胸部应用的可行性。材料与方法:(1)随机选择肺部感染的患儿30例,先常规剂量(150mAs)扫描,再在感染灶局部加作低剂量扫描,剂量为50,35及15mAs。其他参数为:120kV,床进28.8mm/圈,0.5s/圈,16×1.5mm准直,重建层厚及间隔均为3mm。分别记录不同剂量扫描时的CT权重剂量指数(CTDIw)及剂量长度乘积(DLP)。(2)由2位高年资医师按优、良、合格及不合格的等级盲法评价不同剂量的图像质量,结果进行统计学处理。结果:(1)小儿胸部35mAs和15mAs的CTDIw与常规剂量150mAs的比值分别为23.0%及10.0%,其DLP与常规剂量比值为23.3%和10.0%。(2)图像质量评价结果:150,50,35,15mAs的可诊断图像χ2检验,肺窗P>0.05,纵膈窗P<0.05,提示上述剂量肺窗图像差异无显著性意义,纵膈窗图像差异有显著性意义。用150,50,35mAs的可诊断图像进行χ2检验,P>0.05,提示其差异亦无显著性意义。结论:多层螺旋CT低剂量扫描适用于小儿胸部检查,在保证图像质量的前提下,采用35mAs左右的扫描条件较为适宜。     

多层螺旋CT低剂量扫描技术在胸部的应用价值

目的研究多层螺旋CT低剂量扫描技术对肺部疾病的诊断价值。方法将51例胸部CT检查者在同一时间分别行常规剂量（200mAs）与低剂量（25mAs）扫描。评定2种剂量对肺部CT常见征象的显示能力。结果在肺部CT常见征象的显示中,除病灶内结节的显示率低剂量扫描较常规剂量低外,其余征象如：钙化、毛刺、支气管征、形态和边缘等二者均无显著差异。结论胸部低剂量扫描技术能作为健康体检或肺部疾病治疗后复查的首选方法。     

多排螺旋CT扫描对骨折的诊断

目的: 普通X线片及CT平扫对于骨折,尤其是隐匿性骨折检出率较低,较易造成漏诊和误诊,随着多排螺旋CT的普及,利用曲面重建(MPR)和容积再现(VR)技术后处理图像,成为诊断隐匿性骨折的理想的影像诊断手段.探讨多排螺旋CT在对骨折的诊断中的临床应用价值。方法: 对213例临床怀疑骨折的患者进行CR摄片再进行多排螺旋CT扫描,通过三维重建技术处理后,得到受检部位二维、三维的图像。结果: 相同的对照组经多排螺旋CT、X线检查检查后,新增33例骨折。结论: 多排螺旋CT扫描及三维重建技术较传统X线平片能对骨折病例做出更正确的诊断。     

多层螺旋CT门静脉成像在评估肝硬化门脉侧枝血管中的价值

目的：评价多层螺旋CT门静脉成像显示门静脉高压的价值。材料与方法：30例门脉高压患者进行了螺旋CT门脉成像检查,其中10例患者又进行了门静脉造影检查(间接法)。30例患者中全部存在侧枝循环,多数病例有2个或2个以上部位侧枝循环。结果：多层螺旋CT门静脉成像不仅显示了肝内门静脉2-3级分支,还显示了整套门脉侧枝血管系统。在三维门脉像上,脾门静脉曲张29例(占96．7％),其中1例脾静脉因栓子部分闭塞而狭窄,另有1例则完全栓塞血管未显示。胃左静脉曲张28例(占93％),食管或食管旁静脉曲张27例(占90％),胃短静脉(胃后静脉)曲张19例(占63％),胃肾分流血管10例(占33％),腹膜后静脉曲张9例(占30％),脐周静脉曲张伴腹壁静脉曲张6例(占20％)。10例患者CT三维门脉像与间接门静脉造影作比较,前者对门静脉及其侧枝循环的显示好于后者。结论：多层螺旋CT门脉成像是门静脉无创性检查的可靠方法,有较高的临床运用价值。     

多排螺旋CT对隐匿性肋骨骨折的诊断价值及最佳复查时间研究

目的:探讨多排螺旋CT对隐匿性肋骨骨折的诊断价值及最佳复查时间。方法:选取2017年7月到2018年7月期间在我院接受治疗的胸部外伤患者95例,在首次检查时均接受了X线平片和多排螺旋CT检查,比较首次检查时X线平片和多排螺旋CT的检出率,比较首次检查时X线平片和多排螺旋CT对不同类型骨折的诊断情况,比较各个时间段复查病例的肋骨骨折数与首次检查时的差异。结果:95例患者中最终86例确诊存在肋骨骨折,首次检查时多排螺旋CT的检出率为95.35%(82/86),高于X线平片的82.56%(71/86)(P0.05)。86例患者最终确定共存在骨折289处,首次检查时X线平片共检出246处,多排螺旋CT共检出274处,多排螺旋CT对线性骨折、凹陷性骨折的检出率高于X线平片(P0.05)。伤后11-20d、伤后41-50d、伤后51-60d的复查肋骨骨折数与首次检查肋骨骨折数比较无统计学差异(P0.05),伤后21-30d、伤后31-40d的复查肋骨骨折数高于首次检查肋骨骨折数(P0.05)。结论:多排螺旋CT对隐匿性肋骨骨折有较高的诊断价值,首次诊断时的检出率明显高于X线平片,伤后21-40d这个时间段是进行复查的较佳时间段,可获得较好效果。     

多层螺旋CT在胰腺癌中的诊断价值

目的:探讨多层螺旋CT在胰腺癌中的诊断价值。方法:回顾性分析2017年2月至2019年2月我院接诊的72例经过手术病理证实的胰腺癌患者。比较多排螺旋CT平扫、动脉期、胰腺期、门脉期的检出率、神经、血管浸润情况、及选择55例正常胰腺组织比较两者多层螺旋CT扫描密度值的差异。结果:多层螺旋CT扫描,平扫、动脉期、胰腺期、门脉期检出率分别为63.89%、77.78%、95.83%、90.28%,胰腺期、门脉期检出率均显著高于平扫、动脉期(P<0.05);多层螺旋CT增强扫描诊断胰腺癌神经浸润的准确性为80.56%(58/72),敏感性为91.07%(51/56),特异性为43.75%(7/16),阳性预测值85.00%(51/60),阴性预测值58.33%(7/12);多层螺旋CT增强扫描诊断胰腺癌血管浸润的准确性为95.83%(69/72),敏感性为80.00%(8/10),特异性为98.39%(61/62),阳性预测值88.89%(8/9),阴性预测值96.83%(61/63);胰腺癌组织多层螺旋CT扫描密度值均显著高于正常胰腺组织密度值,(P<0.05)。结论:多排螺旋CT在胰腺癌中诊断价值高,可帮助临床提供正确诊断,以选择合适的治疗方案。     

不同剂量多排螺旋CT扫描对儿童肺结核的诊断价值比较研究

目的:探讨不同剂量多排螺旋CT扫描对儿童肺结核(PTB)的诊断价值。方法:以我院于2016年5月～2018年11月收治的156例PTB患儿为研究对象,根据患儿年龄分为A组52例(0～5岁)、B组52例(6～9岁)、C组52例(10～14岁)。三组患儿均进行低剂量64排螺旋CT扫描,其中A组剂量为20 MA,B组剂量为30 MA,C组剂量为40 MA,2 d后,三组患儿均进行常规剂量64排螺旋CT扫描,其中A组剂量为100 MA,B组和C组剂量均为150 MA。分别对比A组、B组、C组患儿低剂量与常规剂量CT扫描的扫描效果、图像优良率及辐射剂量。结果:A组、B组、C组患儿低剂量与常规剂量CT扫描对病灶数量、结节、空洞、胸膜粘连、钙化灶的显像率比较差异无统计学意义(P0.05),但A组、B组、C组患儿低剂量CT扫描对毛刺、磨玻璃影的显像率明显低于常规剂量CT扫描(P0.05);A组、B组、C组患儿低剂量与常规剂量CT扫描的图像优良率比较差异无统计学意义(P0.05);与常规剂量CT扫描相比,A组、B组、C组患儿低剂量CT扫描的剂量长度乘积(DLP)、CT剂量指数(CTDIvoI)、CT加权剂量指数(CTDIw)、放射剂量明显更低(P0.05)。结论:使用常规剂量多排螺旋CT扫描对PTB儿童毛刺、磨玻璃影的显像效果较好,但是使用低剂量多排螺旋CT扫描同样能够确保图像的质量,达到诊断要求,并且能够降低对患儿的辐射剂量,在考虑人体健康的前提下,建议使用低剂量多排螺旋CT扫描。     

多层螺旋CT在诊断小儿急性阑尾炎中的应用

目的:探讨多层螺旋CT对小儿急性阑尾炎的诊断价值。方法:回顾分析经临床手术病理证实的53例小儿急性阑尾炎的CT表现特点。所有患儿均行多排CT横断面扫描及MPVR重建。结果:53例中,单纯性阑尾炎2例;急性化脓性阑尾炎伴周围炎4例,其中1例合并紫癜;急性化脓性阑尾炎伴穿孔33例,其中1例合并回肠末端美克尔憩室;坏疽性阑尾炎伴穿孔6例;阑尾脓肿8例。CT平扫以及MPVR重建显示阑尾肿大、增粗(直径大于6mm)30例,阑尾内粪石27例,阑尾周围蜂窝织炎23例,阑尾周围脓肿8例,大量腹水6例。结论:多层螺旋CT扫描及重建技术能为小儿阑尾炎的诊断提供有力依据,提高临床术前诊断能力。     

多层螺旋CT 血管造影在脑动脉瘤中应用

目的:观察多层螺旋CT血管造影对脑动脉瘤的诊断价值.方法:对16例脑动脉瘤患者的多层螺旋CT血管造影结果进行总结分析.结果:多层螺旋CT血管造影的诊断准确性与DSA无明显差异;多层螺旋CT血管造影显示动脉瘤的部位、大小、动脉瘤颈结构及其与周围血管的关系等与手术结果基本符合.结论:多层螺旋CT血管造影对脑动脉瘤的诊断准确率高,具备十分重要的临床应用价值.     

128层螺旋CT对甲状腺结节的诊断价值

目的:探讨128层螺旋CT对甲状腺结节的诊断价值,提高诊断水平.方法:收集48例经手术病理证实为甲状腺结节(结节性甲状腺肿24例,甲状腺腺瘤11例,甲状腺癌13例)患者的CT及临床资料,重点分析平扫及增强后病灶CT值、密度、包膜完整性、钙化有无及钙化形态,然后将有统计学意义的数值进行判别分析.结果:甲状腺结节的平扫、动静脉期CT值对良恶性鉴别无统计学意义(P＞0.05),结节的轮廓、钙化、边缘强化,以及结节体积、密度、增大淋巴结和周围间隙改变等差异有统计学意义(P＞0.05).结论:掌握各种甲状腺结节性病变的CT特点对甲状腺结节的鉴别诊断具有一定的价值.     

多层螺旋CT联合血清糖类抗原19-9、细胞角蛋白19片段抗原、Dickkopf-1蛋白诊断食管癌的临床价值研究

摘要 目的：研究多层螺旋CT（MSCT）联合血清糖类抗原19-9（CA19-9）、细胞角蛋白19片段抗原（CYFRA21-1）、Dickkopf-1蛋白诊断食管癌的临床价值。方法：选择2018年1月～2021年12月江苏省肿瘤医院收治的102例疑似食管癌患者。根据手术病理结果分为恶性组58例以及良性组44例,对所有受试者均进行MSCT扫描,比较两组各项MSCT影像学特征。检测并比较两组血清CA19-9、CYFRA21-1以及Dickkopf-1表达水平。通过Logistic回归建立多指标联合应用的风险预测模型,应用受试者工作特征（ROC）曲线分析MSCT联合血清CA19-9、CYFRA21-1以及Dickkopf-1蛋白诊断食管癌的效能。结果：恶性组MSCT特征表现为形态不规则、边界模糊病例数占比均高于良性组（均P＜0.05）。关联性检验P＜0.05,提示MSCT诊断方法和金标准病理方法显著关联;优势性检验P＞0.05,提示MSCT诊断方法和金标准病理方法优势差异不显著,即MSCT诊断方法是一种较有价值的食管癌诊断方法。恶性组血清CA19-9、CYFRA21-1以及Dickkopf-1表达水平均高于良性组（均P＜0.05）。经ROC曲线分析发现：MSCT联合血清CA19-9、CYFRA21-1以及Dickkopf-1诊断食管癌的曲线下面积（0.863）、灵敏度（0.879）、特异度（0.841）以及约登指数（0.720）均高于MSCT、血清CA19-9、CYFRA21-1以及Dickkopf-1诊断。结论：MSCT联合血清CA19-9、CYFRA21-1以及Dickkopf-1蛋白诊断食管癌的临床价值较高,值得推广应用。     

Isolation and characterization of a rice cDNA similar to the bovine brain-specific 14-3-3 protein gene

We isolated a rice cDNA clone which is similar to the bovine brain-specific 14-3-3 protein (an activator protein of tyrosine and tryptophan hydroxylase involved in the synthetic pathway of monoamine) gene. The deduced amino acid sequence of the cDNA indicated a surprising similarity to a potent inhibitor of Ca²⁺-phospholipid-dependent protein kinase C. DNA blot analysis indicated that this gene is located at more than a single locus in rice genome DNA. Expression of this gene is regulated by external stresses.     

唾液酸化路易斯-X合成关键酶基因的克隆表达

唾液酸化路易斯-X(sialyl lewis X,Slex) 是选择素家族的一个共同糖配体,通过与选择素竞争性地结合炎性细胞,可以抑制炎症反应。通过克隆表达Slex合成过程中的关键酶,在体外进行Slex的生物合成,用于相关乳腺炎防治药物的研发。β-1,4-半乳糖基转移酶(β-1, 4-galactosyltransferase,GT)就是参与Slex生物合成过程的关键酶之一。利用相关软件对牛的GT基因进行了生物信息学的分析,了解了GT的相关理化性质。通过人工合成的方法获得了GT基因的CDS,构建了重组质粒pMD18-GT,并亚克隆至表达载体pPIC9K。通过电转化将线性化的表达质粒pPIC9K-GT整合到宿主菌P. pastoris GS115基因组上,构建了重组酵母GS115-GT。经诱导表达后,SDS-PAGE检测到了目的蛋白条带,证明了此基因在P. pastoris GS115中能够可溶性表达;并用苯酚红法测定了粗酶液的活性,其比酶活为16.4 U/ml,这为其进一步研究奠定了基础。     

The Ontological and Cultural Genesis of Forms of Memorization: Replication of the Experiments of A.N. Leontiev

Information is presented from a replication of the experiments of A.N. Leontiev (1928), and the ontological and cultural genesis of direct and mediated memorization is traced. It was confirmed that each form of memorization develops with a different degree of productivity and in different ways. No confirmation was found for A.N. Leontiev’s postulate that the ontogenesis of memorization is subject to the “parallelogram principle.” The relationship between forms of memorization and the time and nature of mnemic activity is shown. A pronounced decrease was found in the productivity of memorization processes among present-day schoolchildren and undergraduates as compared with the schoolchildren and undergraduates tested by A.N. Leontiev.     

Stereoisomeric flavour compounds LXVII. 2-, 3-, and 4-Alkyl-branched acids,part 1: General approach to the synthesis of the enantiopure acids

A general approach to the synthesis of 2-, 3-, and 4-alkyl-branched acids of high enantiomeric purity is described. The enantiopure 2-alkyl-branched acids are prepared via liquid chromatographic resolution of diastereomeric phenylglycinol amides and their absolute configuration is deduced from the ¹H-NMR data of the separated diastereomers. Chain elongation methods, by Arndt–Eistert synthesis, via 2-alkylated alkyl carbonitrile or by malonic ester synthesis, are used to prepare 3- and 4-alkyl-branched acids of high configurational purity and known absolute configuration starting from the enantiomeric 2-alkyl-branched acids. © 1994 Wiley-Liss, Inc.     

The content of elastin in the uterine cervix

Mature, crosslinked elastin has been isolated from 4 human and 12 monkey uterine cervices. A modification of previous methods for determination of elastin content was devised to quantitate the low amounts of elastin in the crude connective tissue of uterine cervices. The percentage of elastin was found to range between 0.9 and 2.4% and did not appear to change at various stages of gestation.     

Design and synthesis of novel nonpolar host peptides for the determination of the 310- and α-helix compatibilities of α-amino acid buildig blocks: An assessment of α,α-disubstituted glycines

The present work describes three novel nonpolar host peptide sequences that provide a ready assessment of the 3₁₀- and α-helix compatibilities of natural and unnatural amino acids at different positions of small- to medium-size peptides. The unpolar peptides containing Ala, Aib, and a C-terminal p-iodoanilide group were designed in such a way that the peptides could be rapidly assembled in a modular fashion, were highly soluble in solvent mixtures of triflouroethanol and H₂O for CD- and two-dimensional (2D) nmr spectroscopic analyses, and showed excellent crystallinity suited for x-ray structure analysis. To validate our approach we synthesized 9-mer peptides 79a–96 (Table IV), 12-mer peptides 99–110c (Table V), and 10-mer peptides 120a–125d and 129–133 (Table VI and Scheme 8) incorporating a series of optically pure cyclic and open-chain (R)- and (S)-α,α-disubstituted glycines 1–10 (Figure 2). These amino acids are known to significantly modulate the conformations of small peptides. Based on x-ray structures of 9-mers 79a, 80, and 87 (Figures 4–7), 10-mers 124c, 131, and 132 (Figures 9–12), and 12-mer peptide 102b (Figure 13), CD spectra of all peptides recorded in acidic, neutral, and basic media and detailed 2D-nmr analyses of 9-mer peptide 86 and 12-mer 102b, several interesting conformational observations were made. Especially interesting results were obtained using the convex constraint CD analysis proposed by Fasman on 9-mer peptides 79a–d, 80, 81, 86, and 87, which allowed us to determine the relative content of 3₁₀- and α-helical conformations. These results were fully supported by the corresponding x-ray and 2D-nmr analyses. As a striking example we found that the (S)- and (R)-β-tetralin derived amino acids (R)- and (S)-1 show excellent α-helix stabilisation, more pronounced than Aib and Ala. These novel reference peptide sequences should help establish a scale for natural and unnatural amino acids concerning their intrinsic 3₁₀- and α-helix compatibilities at different positions of medium-sized peptides and thus improve our understanding in the folding processes of peptides. © 1997 John Wiley & Sons, Inc. Biopoly 42: 575–626, 1997     

The institutionalization of biology in Mexico in the early 20th century: the conflict between Alfonso Luis Herrera (1865-1942) and Isaac Ochoterena (1885-1950)

The aim of this work is to evaluate the roleplayed by Alfonso Luis Herrera and IsaacOchoterena in the institutionalization ofacademic biology in Mexico in the early 20thcentury. As biology became institutionalized inMexico, Herrera's basic approach to biology wasdisplaced by Isaac Ochoterena's professionalgoals due to the prevailing politicalconditions at the end of 1929. Theconflict arose from two different conceptionsof biology, because Herrera and Ochoterena haddifferent discourses that were incommensurable,not only linguistically speaking, but alsosocioprofessionally. They had different linksto influential groups related to education,having distinct political and socioprofessionalinterests. The conflict between Herrreraand Ochoterena determined the way in whichprofessional biology education has developed inMexico, as well as the advancement in specificresearch subjects and the neglect of others.