Complexity and content of the DNA and RNA in Trypanosoma cruzi

The content and sequence complexity of the nuclear DNA and messenger RNA for epimastigotes of Trypanosoma cruzi were determined. From analysis of nuclear DNA reassociation studies and microspectrofluorometric measurements of laser induced fluorescence of cellular DNA, T. cruzi is found to be a diploid organism with a nuclear DNA content of 2.5 x 10(8) nucleotide pairs (2.8 x 10(-13) g) and a kinetoplast DNA content of 4.9 x 10(7) nucleotide pairs (5.4 x 10(-14) g). Reassociation kinetics of nuclear DNA of average length 0.4 kb reveals three kinetic components: a moderately repetitive component with a reiteration frequency of 5.1 x 10(3) present in 9% of the fragments, a lowly repetitive component with a reiteration frequency of 32 present in 51% of the fragments, and a single-copy component present in 23% of the fragments. By saturation hybridization of total polysomal RNA to 3H-labeled single-copy DNA, it was determined that 68% of the single-copy DNA was represented in the epimastigote polysomal RNA. This corresponds to ca. 12 000 different mRNA species. Of these, ca. 9000 are present as poly(A)+-RNA, while the remaining 3000 appear not to be polyadenylated. Kinetic analysis of the poly(A)+-RNA population indicates it is composed of at least three classes of RNA's of different abundancy levels: two sequences which occur ca. 3000 per cell, ca. 750 sequences which occur about 20 times per cell, and ca. 15 500 sequences which occur 1-2 times per cell.     

部分去背根猫备用背根节和脊髓Ⅱ板层NT-3及其mRNA的表达变化

采用免疫组化和原位杂交技术探讨了部分去背根猫备用背根节 (L6 )和 L3、L5脊髓 II板层 NT-3及其 m RNA的表达变化。结果发现 ,正常组 NT-3及其 m RNA阳性产物主要分布于背根节的大型神经元和少数中、小型神经元。部分去背根后 ,3 d和10 d两时相 NT-3 m RNA大型神经元阳性数明显减少 ,而 NT-3阳性大型神经元数术后 10 d时方明显减少 (P<0 .0 1) ;NT-3及其 m RNA阳性小型细胞数在术后两时相均较正常组者增多 (P<0 .0 1) ;而在中型神经元只有 NT-3阳性神经元数有增加。相对地 ,在脊髓 板层 ,两时相 NT-3阳性神经元及胶质细胞百分数均较正常者明显增加 (P<0 .0 1) ,且以 3 d组者为最明显 ,但均未见 NT-3 m RNA阳性信号。结果表明 ,部分去背根不仅导致背根节各类神经元中 NT-3的表达发生了变化 ,且对 板层 NT-3阳性神经元及胶质细胞数量也有明显影响。提示 NT-3可能在脊髓 板层可塑性中发挥作用     

Pneumococcal carriage among children after four years of routine 10-valent pneumococcal conjugate vaccine use in Brazil: The emergence of multidrug resistant serotype 6C

BackgroundIn 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced free of charge in Brazil as part of the public immunization program. Here we investigated the carriage prevalence, colonization risk factors, capsular types, and antimicrobial resistance among pneumococcal isolates obtained from children in Brazil four years after routine PCV10 use.MethodsBetween September and December 2014, we conducted a cross-sectional study among children < 6 years old who attended one public and two private clinics in Niterói, RJ, Brazil to evaluate pneumococcal nasopharyngeal carriage. Antimicrobial susceptibility and capsular types were determined for all isolates.ResultsOf 522 children, 118 (22.6%) were pneumococcal carriers. Being ≥ 2 years old, attending childcare center, presenting with any symptoms, having acute or chronic respiratory disease, and residing in a slum were associated with pneumococcal carriage. The most prevalent capsular types were 6C (14.5%), 15B/C (11.5%), 11A/D (9.2%), and 6A (7.6%). PCV10 serotypes represented 2.5%. All isolates were susceptible to levofloxacin, rifampicin, and vancomycin. Penicillin non-susceptible pneumococci (PNSP) comprised 39%, with penicillin and ceftriaxone MICs ranging from 0.12–8.0 μg/ml and 0.012–1.0 μg/ml, respectively. The 33 (28%) erythromycin-resistant isolates (MICs of 1.5 to >256 μg/ml) displayed the cMLS_B (72.7%) or M (27.3%) phenotypes, harboring the erm(B) and/or mef(A/E) genes. High non-susceptibility rates (>20%) to clindamycin, erythromycin, penicillin, and tetracycline were largely explained by the prevalence of multidrug resistant (MDR) serotype 6C isolates.ConclusionsEffects of universal childhood PCV10 use on carriage were evident, with the near elimination of PCV10 serotypes. The emergence of MDR serotype 6C isolates, however, is a concern. Ongoing surveillance to monitor serotype 6C increase in invasive diseases is warranted.     

Differentiating human NT2/D1 neurospheres as a versatile in vitro 3D model system for developmental neurotoxicity testing

Developmental neurotoxicity is a major issue in human health and may have lasting neurological implications. In this preliminary study we exposed differentiating Ntera2/clone D1 (NT2/D1) cell neurospheres to known human teratogens classed as non-embryotoxic (acrylamide), weakly embryotoxic (lithium, valproic acid) and strongly embryotoxic (hydroxyurea) as listed by European Centre for the Validation of Alternative Methods (ECVAM) and examined endpoints of cell viability and neuronal protein marker expression specific to the central nervous system, to identify developmental neurotoxins. Following induction of neuronal differentiation, valproic acid had the most significant effect on neurogenesis, in terms of reduced viability and decreased neuronal markers. Lithium had least effect on viability and did not significantly alter the expression of neuronal markers. Hydroxyurea significantly reduced cell viability but did not affect neuronal protein marker expression. Acrylamide reduced neurosphere viability but did not affect neuronal protein marker expression. Overall, this NT2/D1-based neurosphere model of neurogenesis, may provide the basis for a model of developmental neurotoxicity in vitro.     

Rewarded visual items capture attention only in heterogeneous contexts

Reward is known to affect visual search performance. Rewarding targets can increase search performance, whereas rewarding distractors can decrease search performance. We used subcomponents of the N2pc in the event‐related EEG, the N_T (target negativity) and N_D/P_D (distractor negativity/positivity), in a visual search task to disentangle target and distractor processing related to reward. The visual search task comprised homogeneous and heterogeneous contexts in which a target and a colored distractor were embedded. After each correct trial, participants were given a monetary reward that depended on the color of the distractor. We found longer response times for displays with high‐reward distractors compared to displays with low‐reward distractors, indicating reward‐induced interference, however, only for heterogeneous contexts. The N_T component, indicative of attention deployment to the target, showed that target selection was impaired by high‐reward distractors, regardless of the context homogeneity. Processing of distractors was not affected by reward in homogeneous contexts. In heterogeneous contexts, however, high‐reward distractors were more likely to capture attention (N_D) and required more effort to be suppressed (P_D) than low‐reward distractors. In sum the results showed that, despite the fact that target selection is impaired by high‐reward distractors in both homogeneous and heterogeneous background contexts, high‐reward distractors capture attention only in scenarios that foster attentional capture.     

慢性心衰患者NT pro BNP、NF-kB、Hs-CRP联合检测临床意义

目的 观察NT pro BNP、NF-kB、Hs-CRP联合检测对慢性心衰患者的诊断价值.方法 收集92例慢性心衰患者的临床资料,其中心功能(NYHA)Ⅱ级29例,Ⅲ级32例,Ⅳ级31例,另选35例作为健康对照组进行对比分析,检测各组患者NT pro BNP、NF-kB、Hs-CRP水平.结果 心衰组不同心功能分级的患者的NT pro BNP、NF-kB、Hs-CRP水平均高于对照组(P＜0.05),并伴随心功能损伤程度增幅而显著增高.心衰组NT pro BNP、NF-kB、Hs-CRP单项阳性检出率均明显低于联合检测阳性率,差异有统计学意义(P＜0.05).NT pro BNP与NF-kB、Hs-CRP呈正相关(r=0.587、0.519,P＜0.05).结论 NT pro BNP、NF-kB、Hs-CRP水平变化能动态反应心衰患者心功能损伤程度,联合检测可提高心衰患者心功能病变阳性检出率.     

人工合成三糖抗原在结核病血清诊断中的初步评价

目的评价人工合成三糖抗原在结核病血清诊断的应用前景?方法用人工合成的结核杆菌酚糖酯三糖抗原Tb NT P BSA(naturaltrisaccharide phenylpropionate bovineserumalbumin)作抗原,用ELISA法检测了40例结核患者,52个健康对照的血清标本?结果本方法的特异性?敏感性分别为:检测抗Tb NT P BSAIgG抗体时为94.2%和20.0%;检测抗Tb NT P BSAIgM抗体时为79.6%和45.0%?结论该抗原的特异性?敏感性似不理想,有待进一步改进。     

钩藤碱对多巴胺诱导的NT2细胞凋亡的影响

目的:观察钩藤碱(rhnchophylline,Rhy)对多巴胺(dopamine,DA)诱导NT2细胞凋亡的防护作用.方法:以LDH的漏出率反映细胞的生存率;用TUNEL染色法和DNA琼脂糖凝胶电泳法观察NT2神经元凋亡情况;用Western blotting法测定Bcl-2蛋白表达.结果:Rhy在5和50μmol/L的浓度下能显著地抑制由DA所致的乳酸脱氢酶的漏出,以及明显地提高以PMS试剂转化为指标的生存率(P<0.05,P<0.01);在分化的NT2细胞神经元中,转染bcl-2基因的神经元凋亡率明显低于未经bcl-2基因转染的神经元,而Rhy使DA诱导的转染bcl-2基因神经元和未转染bcl-2基因神经元的凋亡率均明显减少;Rhy能抑制DA所致的DNA降解,但Phy对NT2细胞Bcl-2蛋白表达无明显影响.结论:Rhy能对抗DA诱导的NT2细胞的损伤.     

NT超声检查在早孕期胎儿筛查中的临床价值分析

目的：研究将颈项透明层厚度（NT）超声检测。把其应用到早孕期胎儿中,对其检测结果、正常胎儿与异常胎儿的NT的作用与效果。方法：2019年1月～2020年12月,于本院接收并对其早孕期胎儿进行检测的孕妇,共208例,对全部孕妇均应用NT超声对早孕期胎儿进行检测,比较患者的疗效。结果：(1)检测后,异常、正常依次是35例（16.83%）、173例（83.17%）;分娩结局指出,NT超声检测检出无脑儿畸形、露脑畸形、颈部水囊状淋巴管瘤减少依次是2例、1例、6例,总误诊率9例（4.33%）;分娩结局指出,NT超声检测检出脑膜脑膨出、单心室、心脏外翻增多依次是1例、1例、1例,总漏诊率3例（1.44%）。(2)检测后,异常胎儿的颈项透明层（3.63±0.24）mm,相较于正常胎儿颈项透明层（1.84±0.03）mm对比更厚,P<0.05。结论：在对早孕期胎儿进行检测期间,应用NT超声检测,能够改善孕妇检测结果,并提升胎儿畸形的总检出率,能够给临床中早孕期胎儿方面的筛查给予更多的参照。