Novel liquid chromatographic–tandem mass spectrometric methods using silica columns and aqueous–organic mobile phases for quantitative analysis of polar ionic analytes in biological fluids

Use of silica stationary phase and aqueous–organic mobile phases could significantly enhance LC–MS–MS method sensitivity. The LC conditions were compatible with MS detection. Analytes with basic functional groups were eluted with acidic mobile phases and detected by MS in the positive ion mode. Analytes with acid functional groups were eluted with mobile phases at neutral pH and detected by MS in the negative ion mode. Analytes poorly retained on reversed-phase columns showed good retention on silica columns. Compared with reversed-phase LC–MS–MS, 5–8-fold sensitivity increases were observed for basic polar ionic compounds when using silica columns and aqueous–organic mobile phase. Up to a 20-fold sensitivity increase was observed for acidic polar ionic compounds. Silica columns and aqueous–organic mobile phases were used for assaying nicotine, cotinine, and albuterol in biological fluids.     

Cellular Proteins Required for Adeno-Associated Virus DNA Replication in the Absence of Adenovirus Coinfection

We previously reported the development of an in vitro adeno-associated virus (AAV) DNA replication system. The system required one of the p5 Rep proteins encoded by AAV (either Rep78 or Rep68) and a crude adenovirus (Ad)-infected HeLa cell cytoplasmic extract to catalyze origin of replication-dependent AAV DNA replication. However, in addition to fully permissive DNA replication, which occurs in the presence of Ad, AAV is also capable of partially permissive DNA replication in the absence of the helper virus in cells that have been treated with genotoxic agents. Limited DNA replication also occurs in the absence of Ad during the process of establishing a latent infection. In an attempt to isolate uninfected extracts that would support AAV DNA replication, we discovered that HeLa cell extracts grown to high density can occasionally display as much in vitro replication activity as Ad-infected extracts. This finding confirmed previous genetic analyses which suggested that no Ad-encoded proteins were absolutely essential for AAV DNA replication and that the uninfected extracts should be useful for studying the differences between helper-dependent and helper-independent AAV DNA replication. Using specific chemical inhibitors and monoclonal antibodies, as well as the fractionation of uninfected HeLa extracts, we identified several of the cellular enzymes involved in AAV DNA replication. They were the single-stranded DNA binding protein, replication protein A (RFA), the 3′ primer binding complex, replication factor C (RFC), and proliferating cell nuclear antigen (PCNA). Consistent with the current model for AAV DNA replication, which requires only leading-strand DNA synthesis, we found no requirement for DNA polymerase α-primase. AAV DNA replication could be reconstituted with purified Rep78, RPA, RFC, and PCNA and a phosphocellulose chromatography fraction (IIA) that contained DNA polymerase activity. As both RFC and PCNA are known to be accessory proteins for polymerase δ and , we attempted to reconstitute AAV DNA replication by substituting either purified polymerase δ or polymerase for fraction IIA. These attempts were unsuccessful and suggested that some novel cellular protein or modification was required for AAV DNA replication that had not been previously identified. Finally, we also further characterized the in vitro DNA replication assay and demonstrated by two-dimensional (2D) gel electrophoresis that all of the intermediates commonly seen in vivo are generated in the in vitro system. The only difference was an accumulation of single-stranded DNA in vivo that was not seen in vitro. The 2D data also suggested that although both Rep78 and Rep68 can generate dimeric intermediates in vitro, Rep68 is more efficient in processing dimers to monomer duplex DNA. Regardless of the Rep that was used in vitro, we found evidence of an interaction between the elongation complex and the terminal repeats. Nicking at the terminal repeats of a replicating molecule appeared to be inhibited until after elongation was complete.     

猴运动前区皮层神经元在顺序行为中的放电活动

本工作猴运动前区（ＰＭ）皮层神经元在视觉图表引导的有序运动行为中的放电活动,并在与记忆信息完成的空间顺序行为（ＭＳＳ）中的活动作了比较。为为训练三只猴同时学会ＦＲＳ和ＭＳＳ任务。对１１１个神经元的统计分析表明,它们在ＦＲＭＳ和ＭＳＳ暗示期中发生放电频率变化的均有一半以上。反应期里有放电频率变化的比例也很高;图形期里,ＦＲＳ中的比例比ＭＳＳ中的高出很多。它们对不同运动顺序呈现明显的选择性。对在动物完     

Hookworm Anemia in a Peritoneal Dialysis Patient in China

Hookworm infections as well as other intestinal nematodiases are endemic in China. In this case, a 70-year-old male showed symptoms of chest tightness, shortness of breath, and both lower extremities edema. The diagnostic result was chronic renal insufficiency, chronic kidney disease (5th stage), and renal anemia at first. Then, he received treatment with traditional drugs. However, this treatment did not help to alleviate the symptoms of the patient significantly. The results of gastroendoscopy showed hookworms in the duodenum, also confirmed by pathology examination. Anemia was markedly ameliorated after eliminating the parasites. The results mentioned above suggested that ancylostomiasis was the leading causes of anemia in this patient, and the etiology of anemia in uremic patients should be systematically considered. Especially when anemia could not be cured by regular treatments, rare diseases should be investigated.     

玫瑰花红色素及其稳定性研究

以玫瑰花色素作为新型天然食用色素的可行性进行了初步研究。对光、温度、ｐＨ值、氧化介质、还原介质、蔗糖、咸味（ＮａＣｌ）、铝制品（ＦｅＣｌ３）、铜制品（ＣｕＣｌ２）、锡制品（ＳｎＣｌ２）等对色素的稳定性影响,进行了初步探讨。结果表明,该色素对光、热耐受性好;适用ｐＨ值范围宽;耐氧化性较差,耐还原性较好;Ｆｅ＾３＋和Ｓｎ＾２＋对其吸光值有明显影响,Ｃｕ＾２＋、Ａｌ＾３＋、食盐和蔗糖则影响甚微。     

介绍一种改进的研究气孔运动的方法

本文介绍了以液氮现场固定叶样,扫描电镜直接观察（照相）记录气孔形态、分布、日变化等的方法。从给出的实例可以看到该法能成功地记录气孔在一天的动态变化情况。这种方法特别适合于研究叶表皮密被绒毛的植物。     

小麦族植物DNA重复序列研究

近些年来从小麦族植物中分离到了许多DNA重复序列,并对其组织结构特点,物种分布特异性和在染色体上的分布特征做了广泛的研究,其中一些重复序列已被成功地用于检测遐入小麦的外源染色质和小麦族有关种属的进化研究,本文就以上诸方面进行了简要介绍。     

基于内源信号的脑光学成像系统的研制

基于内源信号的脑光学成像技术（ｏｐｔｉｃａｌ ｉｍａｇｉｎｇ ｂａｓｅｄ ｏｎ ｉｎｔｒｉｎｓｉｃ ｓｉｇｎａｌｓ） 是近年出现的研究脑功能的新技术。它因具有高空间分辨率,可连续长时间记录,使用简便, 费用较低等特点,成为在视觉,听觉以及其他各种脑功能研究的有力工具。本文介绍了国内第一套脑光学成像系统的设计和研制,以及用于视觉研究皮层功能方位柱研究的初步结果。     

Inhibition of keratinocyte ferroptosis suppresses psoriatic inflammation

Psoriasis is a common, chronic, and recurrent inflammatory disease. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes. Keratinocyte death is also involved in many pathophysiological conditions and amplifies the inflammatory cascade. As a newly recognized form of cell death, ferroptosis is involved in several inflammatory diseases. In this study, we aimed to investigate a previously unrecognized role for ferroptosis in psoriasis. Ferroptosis is mediated by lipid peroxidation and iron overload. Compared with normal lesions, the mRNA expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (PTGS2), and transferrin receptor (TFRC) were highly expressed in psoriatic lesions, with decreased levels of glutathione peroxidase 4 (GPX4), ferritin light chain (FTL), and ferritin heavy chain 1 (FTH1). The protein levels of ACSL4 and GPX4 were consistent with their mRNA levels. A similar tendency of ferroptosis was also observed in erastin-treated human primary keratinocytes and the Imiquimod (IMQ)-induced model of psoriasis. To investigate the correlation between inflammation and peroxidation, we analyzed single-cell RNA-sequencing data and identified 15 cell types. There was a high correlation between the activity of the lipid oxidation and the Th22/Th17 response in keratinocytes at a single-cell level. Moreover, ferrostatin-1 (Fer-1), a potent inhibitor of lipid peroxidation, suppressed ferroptosis-related changes in erastin-treated keratinocytes and alleviated psoriasiform dermatitis of IMQ-induced models. Additionally, Fer-1 blocked inflammatory responses in vitro and in vivo, reducing the production of cytokines including TNF-α, IL-6, IL-1α, IL-1β, IL-17, IL-22, and IL-23. This study revealed an expression pattern of ferroptosis in which specific molecules enhance inflammatory reactions in psoriasis.Subject terms: Cell death, Diseases     

基于激光雷达数据的物种分布模拟: 以美国加州内华达山脉南部区域食鱼貂分布模拟为例

生态位模型通过拟合物种分布与环境变量之间的关系提供物种空间分布预测, 在生物多样性研究中有广泛应用。激光雷达(LiDAR)是一种新兴的主动遥感技术, 已被大量应用于森林三维结构信息的提取, 但其在物种分布模拟的应用研究比较缺乏。本研究以美国加州内华达山脉南部地区的食鱼貂(Martes pennanti)的分布模拟为例, 探索LiDAR技术在物种分布模拟中的有效性。生态位模型采用5种传统多类分类器, 包括神经网络、广义线性模型、广义可加模型、最大熵模型和多元自适应回归样条模型, 并使用正样本-背景学习(presence and background learning, PBL)算法进行模型校正; 同时对这5种模型使用加权平均进行模型集成, 作为第6个模型。此外, 一类最大熵模型也被用于模拟该物种的空间分布。模型的连续输出和二值输出分别使用AUC (area under the receiver operating characteristic curve)以及基于正样本-背景数据的评价指标F_pb进行评价。结果表明, 仅考虑气候因子(温度和降水)时, 7个模型的AUC和F_pb平均值分别为0.779和1.077; 当考虑LiDAR变量(冠层容重、枝下高、叶面积指数、高程、坡度等)后, AUC和F_pb分别为0.800和1.106。该研究表明, LiDAR数据能够提高食鱼貂空间分布的预测精度, 在物种分布模拟方面存在一定的应用价值。