• 【铁转运蛋白:细胞和全身铁稳态的通道。】 复制标题 收藏 收藏
    DOI:10.1074/jbc.R117.786632 复制DOI
    作者列表:Knutson MD
    BACKGROUND & AIMS: :Cellular iron homeostasis is maintained by iron and heme transport proteins that work in concert with ferrireductases, ferroxidases, and chaperones to direct the movement of iron into, within, and out of cells. Systemic iron homeostasis is regulated by the liver-derived peptide hormone, hepcidin. The interface between cellular and systemic iron homeostasis is readily observed in the highly dynamic iron handling of four main cell types: duodenal enterocytes, erythrocyte precursors, macrophages, and hepatocytes. This review provides an overview of how these cell types handle iron, highlighting how iron and heme transporters mediate the exchange and distribution of body iron in health and disease.
    背景与目标: :铁和血红素转运蛋白与铁还原酶,铁氧化酶和伴侣蛋白协同作用,维持细胞内铁稳态,从而指导铁进入,进入和离开细胞的运动。系统性铁稳态由肝脏衍生的肽激素hepcidin调节。在铁的四种主要细胞类型的高动态铁处理中,很容易观察到细胞与全身铁稳态之间的界面:十二指肠肠上皮细胞,红细胞前体,巨噬细胞和肝细胞。这篇综述概述了这些细胞类型如何处理铁,着重介绍了铁和血红素转运蛋白如何在健康和疾病中介导体内铁的交换和分布。
  • 【发出通知前的传单以鼓励初次接受宫颈筛查的患者:定性研究。】 复制标题 收藏 收藏
    DOI:10.1093/her/cys103 复制DOI
    作者列表:Sadler L,Albrow R,Shelton R,Kitchener H,Brabin L
    BACKGROUND & AIMS: :Cervical screening attendance among women aged 25-29 years in England is lower than at older ages. There is some evidence that pre-notification leaflets motivate women who have not yet considered their response to a health intervention. We aimed to identify key information to motivate young women at their first cervical screening invitation. Six focus groups were conducted, five with young women aged 17-25 registered with a General Practice in Manchester, UK, and one with Practice nurses. Some women took part in two further groups to discuss leaflet design. There was low awareness of the purpose or procedures of cervical screening, and most women were de-motivated by reports of bad experiences. Some intended to be screened, but not immediately after invitation. Screening was viewed as a test for a cancer that affected older women. Since none of the participants believed that they had cervical cancer, screening seemed unnecessary. We conclude that the perception that screening is unimportant when you are young needs to be challenged. Women also need to be better informed of screening procedures. A pre-notification leaflet incorporating key information was designed and will be tested in a randomized trial of complex interventions within the routine cervical screening programme.
    背景与目标: :在英格兰,年龄在25-29岁之间的女性接受子宫颈筛查的比例低于年龄较大的女性。有证据表明,预先通知传单可以激励尚未考虑其对健康干预措施反应的妇女。我们旨在识别关键信息,以激发年轻女性的首次宫颈筛查邀请。进行了六个焦点小组讨论,其中五个在17-21岁的年轻女性中注册了英国曼彻斯特的General Practice,一个在执业护士中进行。一些妇女参加了另外两个小组,讨论传单设计。人们对宫颈筛查的目的或程序认识不足,大多数妇女因不良经历的报道而失去动力。有些打算放映,但不是在邀请后立即放映。筛查被认为是对影响老年妇女的癌症的测试。由于没有一个参与者相信自己患有宫颈癌,因此筛查似乎是不必要的。我们得出的结论是,对年轻时进行筛查并不重要的看法需要受到挑战。还需要使妇女更好地了解筛查程序。设计了包含关键信息的预告传单,并将在常规宫颈筛查计划内的复杂干预措施的随机试验中进行测试。
  • 【蓖麻的悬浮细胞和子叶在糖摄取方面的比较。】 复制标题 收藏 收藏
    DOI:10.1016/S0176-1617(85)80198-X 复制DOI
    作者列表:Cho BH,Komor E
    BACKGROUND & AIMS: :Suspension cells and cotyledons of Ricinus communis were compared as to their uptake properties for sugar and amino acids to reveal whether the previously reported sucrose-specificity of the cotyledon is a specific feature of the cotyledon or of the Ricinus cell in general. The experiments show that suspension cells have a higher hexose uptake activity at low sugar concentration than cotyledons, whereas sucrose cannot be taken up by suspension cells unless it is first hydrolyzed. Amino acids are taken up by suspension cells and by the cotyledons. It is concluded that the highly specific uptake of sucrose without hydrolysis is a special feature of certain specialized cells of the cotyledon, probably the phloem.
    背景与目标: :比较了蓖麻的悬浮细胞和子叶的糖和氨基酸摄取特性,以揭示先前报道的子叶的蔗糖特异性是子叶还是一般的蓖麻细胞的特定特征。实验表明,悬浮细胞在低糖浓度下具有比子叶更高的己糖摄取活性,而蔗糖除非先水解就不能被悬浮细胞吸收。氨基酸被悬浮细胞和子叶吸收。结论是,子叶的某些特化细胞(可能是韧皮部)的高度特异摄取不水解的蔗糖是其特殊特征。
  • 【心房颤动患者异位活动的细胞和分子相关性。】 复制标题 收藏 收藏
    DOI:10.1093/europace/eus282 复制DOI
    作者列表:Voigt N,Dobrev D
    BACKGROUND & AIMS: :Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with increased morbidity and mortality. Current drugs for AF treatment have limited efficacy and a substantial risk of proarrhythmic side effects, making novel drug development critical. Emerging evidence suggests that abnormal intracellular calcium (Ca(2+)) signalling is a key contributor to ectopic (triggered) electrical activity in human AF. Accordingly, atrial Ca(2+)-handling abnormalities underlying ectopic activity may constitute novel mechanism-based therapeutic approaches to treat AF. This article reviews the recent evidence for a role of cellular ectopic activity in human AF pathophysiology, discusses the molecular mechanisms underlying triggered activity in human atrial myocytes, and considers their relevance to the design of novel therapeutic options.
    背景与目标: :房颤(AF)是最常见的心律不齐,并与发病率和死亡率增加相关。当前用于AF治疗的药物具有有限的功效和存在心律不齐副作用的巨大风险,这使得新药开发变得至关重要。新兴证据表明,异常的细胞内钙(Ca(2))信号传导是人类房颤异位(触发)电活动的关键因素。因此,处理异位活动的心房Ca(2)处理异常可能构成治疗AF的新的基于机制的治疗方法。本文回顾了细胞异位活性在人类房颤病理生理中的作用的最新证据,讨论了在人类心房肌细胞中触发活动的潜在分子机制,并考虑了它们与新型治疗方案设计的相关性。
  • 【抑制钠依赖性L-亮氨酸在大鼠脑突触小体中的摄取。】 复制标题 收藏 收藏
    DOI:10.1016/0006-2952(90)90213-5 复制DOI
    作者列表:Tan CH,Ng FH
    BACKGROUND & AIMS: :Synaptosomes isolated from adult rat cerebral cortices were used for studying the uptake of L-leucine by the Na(+)-dependent route. Three non-metabolizable amino acid analogues, which had been used previously to discriminate the Na(+)-dependent A-type uptake system of animal cells, were employed in this study. It was found that Na(+)-dependent uptake of leucine was insensitive to inhibition by 2-aminoisobutyric acid (AIB) and N-methylaminoisobutyric acid (MeAIB) whereas N-methylalanine (NMA) was markedly inhibitory. Inhibition by NMA was stereospecific--only the L-isomer had a pronounced effect. Na(+)-dependent uptake of leucine as well as its inhibition by L-NMA were rather insensitive to changes in pH from 6 to 9. Kinetic analysis of inhibition by L-NMA of Na(+)-dependent uptake revealed a non-competitive type of inhibition with a Ki value of approximately 0.5 mM.
    背景与目标: :从成年大鼠大脑皮层分离的突触体用于研究Na()依赖途径对L-亮氨酸的摄取。在这项研究中使用了三种不可代谢的氨基酸类似物,这些氨基酸类似物先前已用于区分动物细胞的Na(-)依赖性A型摄取系统。发现亮氨酸的Na()依赖性摄取对2-氨基异丁酸(AIB)和N-甲基氨基异丁酸(MeAIB)的抑制不敏感,而N-甲基丙氨酸(NMA)具有明显的抑制作用。 NMA的抑制作用是立体特异性的-只有L-异构体具有明显的作用。 Na()依赖性亮氨酸的摄取及其对L-NMA的抑制作用对pH值从6到9的变化不敏感。动力学分析表明L-NMA对Na()依赖性摄取的抑制作用揭示了一种非竞争性类型Ki值约为0.5 mM的抑制作用。
  • 【阳离子脂质体介导的人免疫缺陷病毒1型Tat蛋白进入细胞的摄取。】 复制标题 收藏 收藏
    DOI:10.1016/s0166-0934(97)00070-0 复制DOI
    作者列表:Fong SE,Smanik P,Smith MC,Jaskunas SR
    BACKGROUND & AIMS: The human immunodeficiency virus type 1 (HIV-1) Tat protein strongly transactivates gene expression from the viral long terminal repeat (LTR) and is required for virus efficient replication. Previous studies have shown that cells scrape-loaded in the presence of purified recombinant Tat can absorb the protein in a receptor-independent fashion. Using recombinant Tat in which cysteine residues were blocked by sulfitolysis to prevent disulfide aggregation (S-Tat) we were unable to observe this phenomenon, possibly because of improper protein folding. In this study we report that the block to cellular uptake could be overcome by mixing S-Tat with a cationic liposome, Lipofectin. When mixed with Lipofectin, S-Tat effected a specific, concentration-dependent transactivation of HIV-1 LTR-directed reporter gene activity in Hela Cells. Cellular uptake was confirmed by Western blot analysis with an anti-Tat antibody. The method described utilizes cells plated in a 96-well format, requires only nanogram quantities of S-Tat protein and is much less labor-intensive than assays involving scrape-loading, making it suitable for use as a high-throughput screen for detecting Tat inhibitors. The method may have applications for the analysis of other recombinant proteins that require uptake into intact cells for determination of functionality and presents a general technique for introducing exogenous proteins into cells.

    背景与目标: 人类免疫缺陷病毒1型(HIV-1)Tat蛋白可以强烈地激活病毒长末端重复序列(LTR)的基因表达,并且是病毒有效复制所必需的。先前的研究表明,在纯化的重组Tat存在下,被刮擦的细胞可以以不依赖受体的方式吸收蛋白质。使用重组Tat,其中半胱氨酸残基被亚硫酸盐分解作用阻止,以防止二硫键聚集(S-Tat),我们无法观察到这种现象,这可能是由于蛋白质折叠不当所致。在这项研究中,我们报道通过将S-Tat与阳离子脂质体Lipofectin混合可以克服对细胞摄取的阻碍。与Lipofectin混合后,S-Tat在Hela细胞中实现了HIV-1 LTR指导的报告基因活性的特异性,浓度依赖性反式激活。用抗Tat抗体通过蛋白质印迹分析确认了细胞摄取。所描述的方法利用以96孔格式铺板的细胞,仅需纳克量的S-Tat蛋白,并且比涉及刮擦试验的劳动强度低得多,使其适合用作检测Tat的高通量筛选抑制剂。该方法可用于分析其他重组蛋白质,这些蛋白质需要摄取完整细胞来确定功能性,并提出了将外源蛋白质引入细胞的一般技术。

  • 【胎球蛋白通过清除剂受体介导肝脏对带负电荷的纳米粒子的摄取。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijpharm.2006.08.025 复制DOI
    作者列表:Nagayama S,Ogawara K,Minato K,Fukuoka Y,Takakura Y,Hashida M,Higaki K,Kimura T
    BACKGROUND & AIMS: :We tried to evaluate the possible involvement of fetuin in the scavenger receptors (SRs)-mediated hepatic uptake of polystyrene nanospheres with the size of 50 nm (NS-50), which has surface negative charge (zeta potential=-21.8+/-2.3 mV). The liver perfusion studies in rats revealed that the hepatic uptake of NS-50 pre-coated with fetuin (NS-50-fetuin) was significantly inhibited by poly inosinic acid (poly I), a typical inhibitor of SRs, whereas that of plain NS-50 or NS-50 pre-coated with BSA (NS-50-BSA) was not. The uptake of NS-50-fetuin by cultured Kupffer cells was also significantly inhibited by poly I, and anti-class A scavenger receptors (SR-A) antibody, suggesting that fetuin on NS-50 mediated the recognition and internalization of NS-50 by Kupffer cells and at least SR-A would be responsible for the uptake. Taken that Western blot analysis confirmed that fetuin certainly adsorbed on the surface of NS-50 after the incubation of NS-50 with serum, the results obtained in the present study indicate that fetuin would be one of the serum proteins that were substantially involved in the hepatic uptake of NS-50 via SRs.
    背景与目标: :我们试图评估胎球蛋白可能参与清道夫受体(SRs)介导的肝脏吸收大小为50 nm(NS-50)的聚苯乙烯纳米球,该表面具有表面负电荷(ζ电位= -21.8 /-2.3 mV)。在大鼠的肝脏灌注研究中发现,典型的SR抑制剂聚肌苷酸(poly I)显着抑制了预先涂有胎球蛋白(NS-50-胎球蛋白)的NS-50对肝的摄取。未预涂BSA的-50或NS-50(NS-50-BSA)。聚I和抗A类清道夫受体(SR-A)抗体也显着抑制了培养的Kupffer细胞对NS-50-胎球蛋白的摄取,表明NS-50上的胎球蛋白介导了NS-50的识别和内在化。枯否细胞的吸收,至少由SR-A引起。认为Western印迹分析证实胎球蛋白在将血清与NS-50孵育后肯定吸附在NS-50的表面上,本研究获得的结果表明胎球蛋白将是实质性参与胎盘蛋白的血清蛋白之一。肝通过SRs吸收NS-50。
  • 【小鼠flt3配体在小鼠中的慢性表达导致循环白细胞水平升高以及与脾纤维化相关的异常细胞浸润。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Juan TS,McNiece IK,Van G,Lacey D,Hartley C,McElroy P,Sun Y,Argento J,Hill D,Yan XQ,Fletcher FA
    BACKGROUND & AIMS: :The effect of chronic expression of flt3 ligand (FL) on in vivo hematopoiesis was studied. Retroviral vector-mediated gene transfer was used in a mouse model of bone marrow transplantation to enforce expression of mouse FL cDNA in hematopoietic tissues. As early as 2 weeks posttransplantation, peripheral blood white blood cell counts in FL-overexpressing recipients were significantly elevated compared with controls. With the exception of eosinophils, all nucleated cell lineages studied were similarly affected in these animals. Experimental animals also exhibited severe anemia and progressive loss of marrow-derived erythropoiesis. All of the FL-overexpressing animals, but none of the controls, died between 10 and 13 weeks posttransplantation. Upon histological examination, severe splenomegaly was noted, with progressive fibrosis and infiltration by abnormal lymphoreticular cells. Abnormal cell infiltration also occurred in other organ systems, including bone marrow and liver. In situ immunocytochemistry on liver sections showed that the cellular infiltrate was CD3+/NLDC145+/CD11c+, but B220- and F4/80-, suggestive of a mixed infiltrate of dendritic cells and activated T lymphocytes. Infiltration of splenic blood vessel perivascular spaces resulted in vascular compression and eventual occlusion, leading to splenic necrosis consistent with infarction. These results show that FL can affect both myeloid and lymphoid cell lineages in vivo and further demonstrate the potential toxicity of in vivo treatment with FL.
    背景与目标: :研究了flt3配体(FL)的慢性表达对体内造血作用的影响。逆转录病毒载体介导的基因转移被用于骨髓移植的小鼠模型中,以增强小鼠FL cDNA在造血组织中的表达。早在移植后2周,与对照组相比,过表达FL的患者外周血白细胞计数显着升高。除了嗜酸性粒细胞外,所有研究的有核细胞谱系在这些动物中都受到类似的影响。实验动物还表现出严重的贫血和骨髓源性红细胞生成的进行性丧失。所有的过度表达FL的动物,但没有一个对照组,在移植后10至13周内死亡。经组织学检查,发现严重脾肿大,进行性纤维化和异常淋巴网状细胞浸润。细胞的异常浸润也发生在其他器官系统中,包括骨髓和肝脏。肝脏切片的原位免疫细胞化学分析显示,细胞浸润为CD3 / NLDC145 / CD11c,但B220-和F4 / 80-浸润,提示树突状细胞和活化T淋巴细胞混合浸润。脾血管周围血管的浸润导致血管受压并最终闭塞,导致脾脏坏死与梗塞相一致。这些结果表明,FL可在体内影响髓样和淋巴样细胞谱系,并进一步证明了用FL进行体内治疗的潜在毒性。
  • 【对非泌乳绵羊的乳腺中的捻转血矛线虫免疫和对蠕虫抗原的细胞反应。】 复制标题 收藏 收藏
    DOI:10.1016/0020-7519(91)90074-h 复制DOI
    作者列表:Adams DB,Colditz IG
    BACKGROUND & AIMS: :Cellular exudates induced by infusion with helminth antigens were examined in non-lactating mammary glands of ewes immune to infection with the abomasal nematode, Haemonchus contortus. Secondary immunological responsiveness was expressed in two ways. Firstly, antigens from adult H. contortus elicited larger eosinophil-rich cellular exudates in immune compared to non-immune ewes. In this situation, secondary responsiveness in the mammary gland must have been generated through abomasal infection with the parasite. Secondly, repeated infusion with the antigens from adult H. contortus increased the size of cellular exudates in both immune and non-immune ewes. Eosinophils predominated but numbers of macrophages and lymphocytes were also increased. In this second situation, secondary responsiveness must have been either supplemented in immune ewes or derived completely in non-immune ewes by contact with helminth antigens through the mammary gland. The helminth antigens which induce eosinophil exudates in the mammary gland may not be potently protective against H. contortus. Furthermore, eosinophil exudation may not be an in vivo correlate of immunity which is directly useful for discriminating protective antigens and applicable to vaccine development. Infusion with antigens from adult forms of either H. contortus or Trichostrongylus colubriformis elicited cellular exudates equally well in immune ewes primed by infusion with H. contortus adult antigens 7 days beforehand. In addition, antigens from infective larvae of H. contortus elicited cellular exudates more potently than antigens from adult worms. However, vaccination with irradiated larvae has shown that species-specific protective immunity for H. contortus is stronger than cross-protective immunity conferred by T. colubriformis.(ABSTRACT TRUNCATED AT 250 WORDS)
    背景与目标: :在非泌乳性母羊的乳腺中检查了通过注入蠕虫抗原诱导的细胞渗出液,该母乳对原虫线虫Haemonchus contortus的感染免疫。二级免疫反应性以两种方式表达。首先,与非免疫母羊相比,来自成年H. contortus的抗原在免疫中引起较大的富含嗜酸性粒细胞的细胞分泌物。在这种情况下,乳腺的继发性反应一定是通过寄生虫的寄生虫感染而产生的。其次,反复输注来自成年弯曲杆菌的抗原会增加免疫母羊和非免疫母羊中细胞渗出液的大小。嗜酸性粒细胞占主导,但巨噬细胞和淋巴细胞的数量也增加。在第二种情况下,必须通过免疫母羊与蠕虫抗原接触,在免疫母羊中补充次级反应性,或者在非免疫母羊中完全衍生出次级反应性。在乳腺中诱导嗜酸性粒细胞渗出液的蠕虫抗原可能无法有效地抵抗捻转嗜血杆菌。此外,嗜酸性粒细胞渗出可能不是免疫的体内相关性,其直接用于区分保护性抗原并且可用于疫苗开发。输注来自成人的Con。contortus或Trichostrongylus colubriformis的抗原在7天内通过输注Contortus的成年抗原引发的免疫母羊中,细胞渗出液的诱导效果相同。另外,与来自成虫的抗原相比,来自扭曲嗜血杆菌的幼虫的抗原更有效地引起细胞渗出液。然而,用辐照过的幼虫进行的疫苗接种已表明,对棉铃虫的物种特异性保护性免疫力比colubriformis赋予的交叉保护性免疫力强(摘要截短为250字)。
  • 【逆向工程细胞系统的贝叶斯方法:非线性高斯网络的仿真研究。】 复制标题 收藏 收藏
    DOI:10.1186/1471-2105-8-S5-S2 复制DOI
    作者列表:Ferrazzi F,Sebastiani P,Ramoni MF,Bellazzi R
    BACKGROUND & AIMS: BACKGROUND:Reverse engineering cellular networks is currently one of the most challenging problems in systems biology. Dynamic Bayesian networks (DBNs) seem to be particularly suitable for inferring relationships between cellular variables from the analysis of time series measurements of mRNA or protein concentrations. As evaluating inference results on a real dataset is controversial, the use of simulated data has been proposed. However, DBN approaches that use continuous variables, thus avoiding the information loss associated with discretization, have not yet been extensively assessed, and most of the proposed approaches have dealt with linear Gaussian models. RESULTS:We propose a generalization of dynamic Gaussian networks to accommodate nonlinear dependencies between variables. As a benchmark dataset to test the new approach, we used data from a mathematical model of cell cycle control in budding yeast that realistically reproduces the complexity of a cellular system. We evaluated the ability of the networks to describe the dynamics of cellular systems and their precision in reconstructing the true underlying causal relationships between variables. We also tested the robustness of the results by analyzing the effect of noise on the data, and the impact of a different sampling time. CONCLUSION:The results confirmed that DBNs with Gaussian models can be effectively exploited for a first level analysis of data from complex cellular systems. The inferred models are parsimonious and have a satisfying goodness of fit. Furthermore, the networks not only offer a phenomenological description of the dynamics of cellular systems, but are also able to suggest hypotheses concerning the causal interactions between variables. The proposed nonlinear generalization of Gaussian models yielded models characterized by a slightly lower goodness of fit than the linear model, but a better ability to recover the true underlying connections between variables.
    背景与目标: 背景技术:反向工程蜂窝网络目前是系统生物学中最具挑战性的问题之一。动态贝叶斯网络(DBN)似乎特别适合通过对mRNA或蛋白质浓度的时间序列测量结果进行分析来推断细胞变量之间的关系。由于评估真实数据集上的推理结果存在争议,因此提出了使用模拟数据的建议。然而,尚未对使用连续变量,从而避免与离散化相关的信息丢失的DBN方法进行了广泛的评估,并且大多数提议的方法已经处理了线性高斯模型。
    结果:我们提出了动态高斯网络的一般化,以适应变量之间的非线性依赖性。作为测试新方法的基准数据集,我们使用了发芽酵母中细胞周期控制数学模型的数据,真实地再现了细胞系统的复杂性。我们评估了网络描述蜂窝系统动态的能力及其在重构变量之间真正的因果关系上的精度。我们还通过分析噪声对数据的影响以及不同采样时间的影响,测试了结果的鲁棒性。
    结论:结果证实具有高斯模型的DBN可以有效地用于复杂细胞系统数据的第一级分析。推断的模型是简约的,并且具有令人满意的拟合优度。此外,这些网络不仅提供了细胞系统动力学的现象学描述,而且还能够提出有关变量之间因果关系的假设。提出的高斯模型非线性泛化得出的模型的拟合优度比线性模型低,但具有恢复变量之间真正基础联系的能力。
  • 【胶原蛋白的硬度调节细胞的收缩和基质重塑基因的表达。】 复制标题 收藏 收藏
    DOI:10.1002/jbm.a.31423 复制DOI
    作者列表:Karamichos D,Brown RA,Mudera V
    BACKGROUND & AIMS: :Cell-level mechanical and 3D spatial cues are essential to the organization and architecture of new tissues that form during growth, repair or in bioreactors. Fibroblast-seeded 3D collagen constructs have been used as bioartifical extracellular matrix (ECM) providing a 3D environment to embedded resident cells. As cells attach to scaffold fibrils, they generate quantifiable contractile forces which depend on cell type, cell attachment, cell density, growth factors, and matrix stiffness. The aim of this study was to quantify the cytomechanical and molecular responses of human dermal (HDF) and neonatal foreskin fibroblasts (HNFF) seeded in constructs of increased stiffness. We also tested the effect of blocking early attachment using serum starvation on these outputs. Constructs were placed under uniaxial strains of 0-10% to increase scaffold stiffness, prior to gel contraction, and force generation was monitored using a tensional culture force monitor (t-CFM). Increased matrix stiffness reduced generation of quantifiable cellular force (up to 70%) over 24 h in both cell types and delayed the onset of measurable contraction (upto sevenfold). The delay of measurable force generation was cell lineage dependent but not FCS dependent. Gene expression of MMP-2, TIMP-2, and collagen type III expression in HDFs were significantly upregulated in constructs of increased stiffness. HNFFs did not show any significant changes in these gene expressions indicating a lineage specific response.
    背景与目标: :细胞水平的机械和3D空间线索对于在生长,修复或生物反应器中形成的新组织的组织和架构至关重要。成纤维细胞播种的3D胶原构建体已被用作生物人工细胞外基质(ECM),为嵌入式驻留细胞提供3D环境。当细胞附着到支架原纤维上时,它们产生可量化的收缩力,该收缩力取决于细胞类型,细胞附着,细胞密度,生长因子和基质刚度。这项研究的目的是量化播种在增加刚度的结构中的人类真皮(HDF)和新生儿包皮成纤维细胞(HNFF)的细胞力学和分子反应。我们还测试了在这些输出上使用血清饥饿来阻止早期附着的效果。在凝胶收缩之前,将构建体置于0-10%的单轴应变下以增加支架的刚度,并使用张力培养力监测器(t-CFM)监测力的产生。基质刚度的提高减少了两种细胞类型在24小时内可量化细胞力的产生(高达70%),并延迟了可测量收缩的发生(高达七倍)。可测力产生的延迟取决于细胞谱系,而不取决于FCS。在刚度增加的结构中,HDF中MMP-2,TIMP-2和III型胶原的基因表达显着上调。 HNFFs在这些基因表达中未显示任何显着变化,表明谱系特异性反应。
  • 【黄曲霉毒素B1的细胞毒性作用及其与鸡胚原代培养细胞中细胞成分的关系。】 复制标题 收藏 收藏
    DOI:10.1016/0304-4165(90)90109-a 复制DOI
    作者列表:Iwaki M,Kitagawa T,Akamatsu Y,Aibara K
    BACKGROUND & AIMS: :We have examined the cytotoxicity and cellular incorporation of aflatoxin B1 (AFB1) in several types of established and primary cultured cells. The inhibition of DNA synthesis by AFB1 at 1 microgram/ml was about 0-30% in the established cell lines, including human hepatic cells. In chicken primary hepatocytes, however, DNA synthesis as well as RNA and protein syntheses were strongly inhibited by much lower concentrations of AFB1, e.g., 0.1 microgram/ml. In contrast, chicken primary fibroblasts showed almost no significant response to the toxin. Microsomal cytochrome P-450 activities in hepatic tissues were 10-20-fold higher than those in fibroblastic tissues. The amount of [3H]AFB1 incorporated into acid-insoluble materials in the primary hepatocytes was also 10-100-fold more than that in the primary fibroblasts. However, a significant amount of AFB1, which was enough to induce cytotoxic effects on the primary hepatocytes, could be incorporated into the primary fibroblasts when the concentrations of AFB1 were increased. Characterization of the AFB1-associated cellular components showed that most of them were DNA, RNA, and proteins in the primary hepatocytes, while in the primary fibroblasts a large portion of the incorporated AFB1 was recovered from lipid fractions. In addition, the selective binding of [3H]AFB1 to several proteins was observed only in the primary hepatocytes. The possible role of the AFB1-binding proteins are also discussed.
    背景与目标: :我们已经研究了黄曲霉毒素B1(AFB1)在几种类型的已建立和原代培养细胞中的细胞毒性和细胞掺入。在已建立的细胞系(包括人肝细胞)中,AFB1对DNA合成的抑制作用为1微克/毫升,约为0-30%。但是,在鸡原代肝细胞中,DNA的合成以及RNA和蛋白质的合成受到浓度低得多的AFB1(例如0.1微克/毫升)的强烈抑制。相反,鸡原代成纤维细胞对毒素几乎没有明显反应。肝组织中的微粒体细胞色素P-450活性比成纤维细胞组织中的微粒体细胞色素P-450活性高10-20倍。在原代肝细胞中掺入酸不溶性物质中的[3H] AFB1的量也比原代成纤维细胞高10-100倍。但是,当AFB1浓度增加时,足以诱导对原代肝细胞的细胞毒性作用的大量AFB1可以掺入原代成纤维细胞中。与AFB1相关的细胞成分的表征表明,它们中的大多数是原代肝细胞中的DNA,RNA和蛋白质,而在原代成纤维细胞中,大部分掺入的AFB1是从脂质组分中回收的。此外,仅在原代肝细胞中观察到[3H] AFB1与几种蛋白质的选择性结合。还讨论了AFB1结合蛋白的可能作用。
  • 【线粒体:氧化还原活动和细胞窘迫控制的枢纽。】 复制标题 收藏 收藏
    DOI:10.1007/s11010-007-9520-8 复制DOI
    作者列表:Kakkar P,Singh BK
    BACKGROUND & AIMS: :In their reductionist approach in unraveling phenomena inside the cell, scientists in recent times have focused attention to mitochondria. An organelle with peculiar evolutionary history and organization, it is turning out to be an important cell survival switch. Besides controlling bioenergetics of a cell it also has its own genetic machinery which codes 37 genes. It is a major source of generation of reactive oxygen species, acts as a safety device against toxic increases of cytosolic Ca2+ and its membrane permeability transition is a critical control point in cell death. Redox status of mitochondria is important in combating oxidative stress and maintaining membrane permeability. Importance of mitochondria in deciding the response of cell to multiplicity of physiological and genetic stresses, inter-organelle communication, and ultimate cell survival is constantly being unraveled and discussed in this review. Mitochondrial events involved in apoptosis and necrotic cell death, such as activation of Bcl-2 family proteins, formation of permeability transition pore, release of cytochrome c and apoptosis inducing factors, activation of caspase cascade, and ultimate cell death is the focus of attention not only for cell biologists, but also for toxicologists in unraveling stress responses. Mutations caused by ROS to mitochondrial DNA, its inability to repair it completely and creation of a vicious cycle of mutations along with role of Bcl-2 family genes and proteins has been implicated in many diseases where mitochondrial dysfunctions play a key role. New therapeutic approaches toward targeting low molecular weight compounds to mitochondria, including antioxidants is a step toward nipping the stress in the bud.
    背景与目标: :最近,科学家们以还原论的方法揭示了细胞内部的现象,将注意力集中在线粒体上。具有独特的进化历史和组织的细胞器,事实证明它是重要的细胞存活开关。除了控制细胞的生物能,它还具有自己的遗传机制,可编码37个基因。它是产生活性氧的主要来源,是防止细胞溶质Ca2毒性增加的安全装置,其膜通透性转变是细胞死亡的关键控制点。线粒体的氧化还原状态在抵抗氧化应激和维持膜通透性方面很重要。在决定细胞对多种生理和遗传压力,细胞间通讯以及最终细胞存活的反应中,线粒体的重要性正在不断地被探讨和讨论。涉及凋亡和坏死细胞死亡的线粒体事件,例如Bcl-2家族蛋白的激活,通透性过渡孔的形成,细胞色素c和凋亡诱导因子的释放,胱天蛋白酶级联的激活以及最终细胞死亡等,并不是人们关注的焦点。不仅适用于细胞生物学家,还适用于毒理学家,以阐明压力反应。 ROS引起的线粒体DNA突变,其无法完全修复,突变的恶性循环以及Bcl-2家族基因和蛋白质的作用,在许多疾病中都与线粒体功能障碍起着关键作用。将低分子量化合物靶向线粒体(包括抗氧化剂)的新治疗方法是消除发芽压力的一步。
  • 【酵母种马克斯克鲁维酵母中乳糖摄取的模式。】 复制标题 收藏 收藏
    DOI:10.1007/BF00403158 复制DOI
    作者列表:Carvalho-Silva M,Spencer-Martins I
    BACKGROUND & AIMS: :Twelve lactose-assimilating strains of the yeast species Kluyveromyces marxianus and its varieties marxianus, lactis and bulgaricus were studied with respect to transport mechanisms for lactose, glucose and galactose, fermentation of these sugars and the occurrence of extracellular lactose hydrolysis. The strains fell into three groups. Group I (two strains): Fermentation of lactose, glucose and galactose, extracellular lactose hydrolysis, apparent facilitated diffusion of glucose and galactose; Group II (two strains): Lactose not fermented, glucose and galactose fermented and transported by an apparent proton symport, extracellular hydrolysis of lactose present (one strain) or questionable; Group III (eight strains): Lactose, glucose and galactose fermented, lactose transported by an apparent proton symport mechanism, extracellular hydrolysis of lactose and transport modes for glucose and galactose variable.
    背景与目标: :研究了十二种马克斯克鲁维酵母菌及其同化乳糖菌株,研究了其乳糖,葡萄糖和半乳糖的转运机制,这些糖的发酵以及细胞外乳糖水解的发生。菌株分为三组。第一组(两个菌株):乳糖,葡萄糖和半乳糖的发酵,细胞外乳糖的水解,葡萄糖和半乳糖的明显促进扩散;第二组(两个菌株):未发酵的乳糖,通过明显的质子同质发酵和运输的葡萄糖和半乳糖,存在的乳糖的细胞外水解(一个菌株)或可疑;第三组(八株):发酵的乳糖,葡萄糖和半乳糖,通过明显的质子交换机制运输的乳糖,乳糖的细胞外水解以及葡萄糖和半乳糖可变的运输方式。
  • 【铝和哇巴因对突触体胆碱摄取,乙酰胆碱释放和(Na / K)ATPase的比较作用。】 复制标题 收藏 收藏
    DOI:10.1016/j.tox.2007.04.017 复制DOI
    作者列表:Silva VS,Nunes MA,Cordeiro JM,Calejo AI,Santos S,Neves P,Sykes A,Morgado F,Dunant Y,Gonçalves PP
    BACKGROUND & AIMS: :Closing the gap between adverse health effects of aluminum and its mechanisms of action still represents a huge challenge. Cholinergic dysfunction has been implicated in neuronal injury induced by aluminum. Previously reported data also indicate that in vivo and in vitro exposure to aluminum inhibits the mammalian (Na(+)/K(+))ATPase, an ubiquitous plasma membrane pump. This study was undertaken with the specific aim of determining whether in vitro exposure to AlCl(3) and ouabain, the foremost utilized selective inhibitor of (Na(+)/K(+))ATPase, induce similar functional modifications of cholinergic presynaptic nerve terminals, by comparing their effects on choline uptake, acetylcholine release and (Na(+)/K(+))ATPase activity, on subcellular fractions enriched in synaptic nerve endings isolated from rat brain, cuttlefish optic lobe and torpedo electric organ. Results obtained show that choline uptake by rat synaptosomes was inhibited by submillimolar AlCl(3), whereas the amount of choline taken up by synaptosomes isolated from cuttlefish and torpedo remained unchanged. Conversely, choline uptake was reduced by ouabain to a large extent in all synaptosomal preparations analyzed. In contrast to ouabain, which modified the K(+) depolarization evoked release of acetylcholine by rat, cuttlefish and torpedo synaptosomal fractions, AlCl(3) induced reduction of stimulated acetylcholine release was only observed when rat synaptosomes were challenged. Finally, it was observed that the aluminum effect on cuttlefish and torpedo synaptosomal (Na(+)/K(+))ATPase activity was slight when compared to its inhibitory action on mammalian (Na(+)/K(+))ATPase. In conclusion, inhibition of (Na(+)/K(+))ATPase by AlCl(3) and ouabain jeopardized the high-affinity (Na(+)-dependent, hemicholinium-3 sensitive) uptake of choline and the Ca(2+)-dependent, K(+) depolarization evoked release of acetylcholine by rat, cuttlefish and torpedo synaptosomal fractions. The effects of submillimolar AlCl(3) on choline uptake and acetylcholine release only resembled those of ouabain when rat synaptosomes were assayed. Therefore, important differences were found between the species regarding the cholinotoxic action of aluminum. The variability of (Na(+)/K(+))ATPase sensitivity to aluminum of cholinergic neurons might contribute to their differential susceptibility to this neurotoxic agent.
    背景与目标: :缩小铝对健康的不良影响及其作用机制之间的差距仍然是巨大的挑战。胆碱能功能障碍与铝诱导的神经元损伤有关。先前报道的数据还表明,体内和体外暴露于铝会抑制普遍存在的质膜泵哺乳动物(Na()/ K())ATPase。进行这项研究的特定目的是确定体外暴露于AlCl(3)和ouabain(最主要利用的(Na()/ K())ATPase的选择性抑制剂)是否诱导胆碱能突触前神经末梢的类似功能修饰。比较它们对胆碱摄取,乙酰胆碱释放和(Na()/ K())ATPase活性的影响,对富集自大鼠脑,墨鱼视神经叶和鱼雷电器官的突触神经末梢富集的亚细胞级分的影响。获得的结果表明,大鼠毫微摩尔的AlCl(3)抑制了大鼠突触小体对胆碱的摄取,而从墨鱼和鱼雷分离的突触小体对胆碱的摄取量却保持不变。相反,在所有分析的突触体制剂中,哇巴因在很大程度上降低了胆碱的摄取。相比于哇巴因,它修改了大鼠,乌贼和鱼雷突触小体部分的K()去极化引起乙酰胆碱的释放,仅当挑战大鼠突触体时才观察到AlCl(3)诱导的乙酰胆碱释放减少。最后,观察到铝对墨鱼和鱼雷突触体(Na()/ K())ATPase的活性与其对哺乳动物(Na()/ K())ATPase的抑制作用相比是轻微的。总之,AlCl(3)和哇巴因对(Na()/ K())ATPase的抑制作用损害了胆碱和Ca(2)依赖的高亲和力(Na(依赖),hemicholinium-3敏感)的摄取。 ,K()去极化引起大鼠,墨鱼和鱼雷突触体级分释放乙酰胆碱。当测定大鼠突触小体时,亚毫摩尔AlCl(3)对胆碱摄取和乙酰胆碱释放的影响仅类似于哇巴因。因此,在物种之间发现了关于铝的胆碱毒性作用的重要差异。 (Na()/ K())ATPase对胆碱能神经元铝的敏感性的变异性可能有助于它们对这种神经毒性剂的敏感性不同。

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