974 resultados para Prostaglandina E2
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A asma é um distúrbio crônico pulmonar caracterizado por inflamação, obstrução e remodelamento brônquico, levando a sintomas como sibilo, tosse e falta de ar. A terapia antiasmática consiste em corticosteroides inalados e agonistas β2 de curta ou longa duração. O tratamento é limitado por efeitos colaterais e refratariedade de alguns pacientes, justificando a necessidade de novas terapias. Estudos demonstram que a 15-deoxy-delta- 12,14-prostaglandina J2 (15d-PGJ2), um ligante endógeno de receptores ativados por proliferadores de peroxissomos do tipo gama (PPAR-γ), é capaz de reduzir a expressão de citocinas pró-inflamatórias, o que pode resultar em benefícios no tratamento de doenças com esse perfil. O objetivo deste estudo foi avaliar o potencial anti-inflamatório e antiasmático da 15d-PGJ2 em modelos experimentais de asma. Camundongos A/J machos foram sensibilizados nos dias 0 e 7 através de injeção subcutânea (s.c.), contendo ovoalbumina (OVA) e Al(OH)3, e desafiados com 4 instilações intranasais (i.n.) de OVA em intervalos semanais. O tratamento com 15d-PGJ2 (30 e 100 g/Kg, s.c.) foi realizado 30 min antes dos desafios a partir da terceira provocação antigênica. Em outro modelo, camundongos A/J foram desafiados intranasalmente com extrato de ácaro 3 vezes por semana durante 3 semanas. As administrações de 15d-PGJ2 (30, 70 e 100 g/Kg, s.c. e 0,65; 1,5 e 2,3 g/animal, i.n.) foram realizadas a partir da 3 semana, 30 min antes dos desafios. As análises ocorreram 24 h após o último desafio. Nossos resultados mostraram que, em camundongos previamente sensibilizados e desafiados com OVA, a administração de 15d-PGJ2 limitou significativamente o influxo peribrônquico de eosinófilos e neutrófilos, bem como a produção de muco por células caliciformes e fibrose sub-epitelial, além da hiperreatividade das vias aéreas e produção de IL-5. A redução do epitélio brônquico e das citocinas IL-13 e TNF-α foram observadas somente na maior dose administrada. No modelo HDM a inflamação e o remodelamento foram atenuados em todas as doses administradas do composto, enquanto que a hiperresponssividade brônquica foi inibida apenas nas doses de 70 e 100 μg/Kg (via sistêmica) e na dose intermediária dada topicamente (1,5 μg/animal, i.n.). Os níveis de citocinas foram atenuados pelo tratamento subcutâneo, porém somente os níveis de IL-17, eotaxina-1 e TNF-α foram inibidos com a dose intranasal de 0,65 g/animal. O aumento da expressão de NF-κB, induzido por provocação com HDM também foi reduzido significativamente pela administração de 15d-PGJ2. Em conjunto, nossos dados indicam que o tratamento com 15d-PGJ2 inibe alterações cruciais associadas à patogênese da asma, em modelos experimentais distintos da doença, demonstrando possuir grande potencial para controlar e reverter inflamação, hiperreatividade e remodelamento pulmonar desencadeados por provocação alérgica.
Resumo:
T淋巴细胞表面的TRBC受体不同介导E花结形成的E受体(CO_(2))和E2分子 。CD_(2)的配体, 人红细胞表面的CD58(LFA-3)和绵羊红细胞表面的T11TS, S42, S14及S110-220, 与TRBC受体的配体无关,TRBC玫瑰花结的形成是通过不同E 花结和人自身玫瑰花结的受体—配体相互作用来实现的, 进一步表明, 人和猴T 淋巴细胞表面和TRBC表面,可能都有独特的蛋白质分子介导TRBC玫瑰花结的形成 。表4参16
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报道了用高电荷态离子1 2 9Xe30 + (15 0keV)轰击金属Ni表面 ,激发的 2 0 0— 10 0 0nmNiⅠ和NiⅡ的特征光谱线的实验结果 .实验结果表明 :用电荷态足够高的离子作光谱激发源 ,无需很强的束流强度 (nA量级 ) ,便可有效地产生原子和离子的复杂组态间跃迁所形成的可见光波段的特征谱线 ,特别是NiⅠ和NiⅡ偶极禁戒的电四极跃迁E2和磁偶极跃迁M1的特征光谱线 .通过分析发现 ,在禁戒跃迁的谱线中 ,有些是电子组态相同而原子态不同的偶极禁戒跃迁光谱线而且NiⅡ的 6 84 84nm谱线较强
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Two-electron-one-photon (TEOP) M1 and E2 transition energies, line strengths and transition probabilities between the states of the 2p(3) and 2s(2)2p odd configurations for B-like ions with 18 <= Z <= 92 have been calculated using the GRASP2K package based on the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Employing active-space techniques to expand the configuration list, we have systematically considered the valence, core-valence and core-core electron correlation effects. Breit interaction and quantum electrodynamical (QED) effects were also included to correct atomic state wavefunctions and the corresponding energies. Influences of electron correlation, Breit interaction and QED effects on transition energies and line strengths of the TEOP M1 and E2 transitions were analysed in detail. The present results were also compared with other theoretical and experimental values.
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本文采用组织学手段研究了牙鲆性腺在分化、发育和成熟过程中的变化。然后,通过放射性免疫方法(RIA)测定了牙鲆仔稚幼鱼全组织匀浆液中的性类固醇激素—睾酮(T)和雌二醇(E2)的含量,并结合牙鲆血清中T和E2含量的年周期测定,从内分泌学水平探讨了T和E2在其性腺分化、发育和成熟过程中水平的变化规律。同时,采用高温和雌性激素对性腺未分化的普通和雌核发育牙鲆仔稚鱼进行诱导处理,获得了较高比例的雄性鱼/假雄鱼或100%雌性鱼;并研究了这些外界环境因子对牙鲆性腺分化、性别比率及体内T和E2水平的影响,藉此探讨了牙鲆性别决定与性腺分化的细胞学和内分泌学机制。 对牙鲆仔稚幼鱼性腺的组织切片观察发现,培育水温18~20℃下,孵化后第45天、平均全长<22.0±2.8 mm的牙鲆,其性腺分化尚未开始,属于原始性腺;在孵化后70日龄、平均全长为38.0±1.7 mm左右,部分个体中观察到卵巢的雏形,其余个体的性腺在此阶段以及之后的一段时间内变化并不明显;到了第110天、平均全长达到86.5±5.9 mm时,雌性个体卵巢出现了卵原细胞向卵母细胞的转变,标志着卵巢分化的结束。在90日龄、平均全长为63.5±3.4 mm的雄性牙鲆中,精原细胞快速增殖,并观察到了输精管结构;进一步的细胞学分化则出现在100日龄、平均全长为76.0±8.6 mm的个体中,此时可以看到精小叶的形成;在平均全长为140.0±15.2 mm时,精巢中出现初级精母细胞,标志着性腺分化的基本完成。 对牙鲆仔稚幼鱼全组织匀浆和成鱼血清中的T和E2水平的比较发现,在全长为6 mm左右的仔鱼中T和E2含量均较高。随后,在性腺分化过程中T含量大大降低,E2的含量急剧增高,而性腺分化后期E2含量又降到较低的水平。在雄性牙鲆成鱼中, 从精巢第Ⅲ期开始,T含量随着精巢的发育而增加,到了精巢第Ⅴ期性腺发育成熟并排精后,又降低到较低的水平;E2含量在从精巢第Ⅲ期发育至精巢第Ⅴ期过程中略呈降低的趋势,但是总体上来说没有明显的差异。在雌性牙鲆成鱼中,卵巢从第Ⅱ期到第Ⅳ期的过程中,T水平逐渐升高,在第Ⅴ期时则明显降低;而E2含量在卵巢第Ⅱ期时保持较低的水平,随着卵巢的发育,E2含量逐渐增高,在卵巢第Ⅳ期时达到最高水平,在第Ⅴ期产卵后又有所降低。在雌雄个体中T和E2均呈现周期性的变化。5月份随着水温的升高,雄性个体T和E2含量显著上升;到了9月份又逐渐下降至最低值。雌性个体E2含量自3月份开始增高,在5月份急剧升高,并在6月份达到最高值;在7月份的时候,E2突然降低,而到了8月份又有所回升;9月份之后E2逐渐降低并在1月份左右降到最低;而T的含量分别在2月份和6月份出现两次高峰。 温度诱导牙鲆幼鱼性腺分化的结果表明,牙鲆中存在明显的TSD机制,即其性腺分化因饲育水温的不同而变化:在一定温度范围内,随着饲育温度的增加,牙鲆的雄性比例逐渐增高,常温对照组和21℃组中的雄性比例分别为51.62%、60.00%,而在24℃和28℃高温组中,雄性比例显著高于对照组,分别达到73.33%和87.27%。T和E2含量测定显示,在性腺分化时期,高温和对照组中T含量没有明显的变化,而温度处理组中的E2水平则低于对照组,特别是在28℃高温组,其E2水平显著低于对照组(P<0.05)。外源E2处理性腺未分化的牙鲆幼鱼的结果也表明,牙鲆的死亡率与雌性化比率均为雌性激素剂量依赖型的。随着外源E2剂量的增加,雌性比率增加,但同时死亡率也增高。此期间T和E2水平比较发现,在性腺分化时期,对照组中的T含量稍高于雌激素处理组;而对照组中的E2含量高于0.2 ppm和2 ppm两个低剂量组,却低于20 ppm和100 ppm两个高剂量组。 同时,还对人工诱导培育的雌核发育牙鲆和性反转牙鲆进行了性腺发育观察,在所观察的雌核发育牙鲆个体中,其雌性比例为83.33%,而高温28℃饲育群体中的雄性比例(即假雄鱼比例)为91.67%;在雌性个体中,也有一定比例的个体性腺发育不正常,有的性腺发育较小,有的则缺少部分性腺。进一步对雌核发育成体的血清中T和E2含量进行测量,发现在普通牙鲆个体中T含量显著低于雌核发育个体,而E2含量则高于雌核发育牙鲆;在雌核发育牙鲆中,性腺发育不正常的个体比性腺发育正常的个体中的T含量稍高,而E2含量则显著低于正常雌核发育牙鲆个体和普通牙鲆个体(P< 0.05)。
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Background and Aim: During carcinogenesis, tumours develop multiple mechanisms to evade the immune system and suppress the anti-tumour immune response. Upregulation of Fas Ligand (FasL/CD95L) expression may represent one such mechanism. FasL is a member of the tumour necrosis factor superfamily that triggers apoptotic cell death following ligation to its receptor Fas. Numerous studies have demonstrated upregulated FasL expression in tumor cells, with FasL expression associated with numerous pro-tumorigenic effects. However, little is known about the mechanisms that regulate FasL expression in tumours. The cyclooxgenase (COX) signalling pathway may play an important role in colon carcinogenesis, via the production of prostaglandins, in particular PGE2. PGE2 signals through four different receptor subtypes, EP1 – EP4. Thus, the aim of this study was to investigate the effect of targeting the PGE2-FasL signaling pathway. Results: (i) PGE2 induces FasL expression via the EP1 receptor in colon cancer cells. (ii) Suppression of FasL expression in colon tumour cells in vivo significantly delays and reduces tumour growth. (iii) Blocking EP1 receptor signaling, or suppression of the EP1 receptor in colon tumour cells, reduces tumour growth in vivo. Suppression of tumour growth correlates in part with suppression of FasL expression. (iv) The reduction in tumour growth is associated with an improved anti-tumour immune response. Tumour infiltration by Treg cells and macrophages was reduced, and the cytotoxic activity of CTL generated from splenocytes isolated from these mice increased. Conclusion: 1) Targeting FasL expression by blocking PGE2-EP1 receptor signalling reduces tumour development in vivo. 2) The mechanism is indirect but is associated with an increased anti-tumour immune response. Thus, unraveling the mechanisms regulating FasL expression and the pro-tumorigenic effects of the EP1 receptor may aid in the search for new therapeutic targets against colon cancer.
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Vertebrate eggs are arrested at Metaphase II by Emi2, the meiotic anaphase-promoting complex/cyclosome (APC/C) inhibitor. Although the importance of Emi2 during oocyte maturation has been widely recognized and its regulation extensively studied, its mechanism of action remained elusive. Many APC/C inhibitors have been reported to act as pseudosubstrates, inhibiting the APC/C by preventing substrate binding. Here we show that a previously identified zinc-binding region is critical for the function of Emi2, whereas the D-box is largely dispensable. We further demonstrate that instead of acting through a "pseudosubstrate" mechanism as previously hypothesized, Emi2 can inhibit Cdc20-dependent activation of the APC/C substoichiometrically, blocking ubiquitin transfer from the ubiquitin-charged E2 to the substrate. These findings provide a novel mechanism of APC/C inhibition wherein the final step of ubiquitin transfer is targeted and raise the interesting possibility that APC/C is inhibited by Emi2 in a catalytic manner.
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Energies of the 54 levels belonging to the (1s(2)2s(2)2p(6)) 3s(2)3p(5), 3s3p(6), 3s(2)3p(4)3d and 3s3p(5)3d configurations of Fe X have been calculated using the GRASP code of Dyall et al. (1989). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Comparisons are made with results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 3%, whereas results for other parameters are probably accurate to better than 20%. Additionally, the agreement between measured and calculated lifetimes is better than 10%.
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Energies and lifetimes are reported for the lowest 375 levels of five Br-like ions, namely SrIV, YV, ZrVI, NbVII, and MoVIII, mostly belonging to the 4s<sup>2</sup>4p<sup>5</sup>, 4s<sup>2</sup>4p<sup>4</sup>4ℓ, 4s4p<sup>6</sup>, 4s<sup>2</sup>4p<sup>4</sup>5ℓ, 4s<sup>2</sup>4p<sup>3</sup>4d<sup>2</sup>, 4s4p<sup>5</sup>4ℓ, and 4s4p<sup>5</sup>5ℓ configurations. Extensive configuration interaction has been included and the general-purpose relativistic atomic structure package (grasp) has been adopted for the calculations. Additionally, radiative rates are listed among these levels for all E1, E2, M1, and M2 transitions. From a comparison with the measurements, the majority of our energy levels are assessed to be accurate to better than 2%, although discrepancies between theory and experiment for a few are up to 6%. An accuracy assessment of the calculated radiative rates (and lifetimes) is more difficult, because no prior results exist for these ions.
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We report calculations of energy levels, radiative decay rates, and lifetimes for transitions among the 3s23p5, 3s3p6, and 3s23p43d configurations of Cl-like W LVIII. The general-purpose relativistic atomic structure package (GRASP) has been adopted for our calculations. Comparisons are made with the most recent results of Mohan et al. (Can. J. Phys. 92, 177 (2014). doi:10.1139/cjp-2013-0348) and discrepancies in lifetimes are noted, up to four orders of magnitude in some instances. Our energy levels are estimated to be accurate to better than 0.5%, whereas results for radiative rates and lifetimes should be accurate to better than 20%.
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CONTEXT: The formation of primordial follicles occurs during fetal life yet is critical to the determination of adult female fertility. Prior to this stage, germ cells proliferate, enter meiosis, and associate with somatic cells. Growth and survival factors implicated in these processes include activin A (INHBA), the neurotrophins BDNF and NT4 (NTF5), and MCL1. The prostaglandins have pleiotrophic roles in reproduction, notably in ovulation and implantation, but there are no data regarding roles for prostaglandins in human fetal ovarian development.
OBJECTIVE: The aim of the study was to investigate a possible role for prostaglandin (PG) E(2) in human fetal ovary development.
DESIGN: In vitro analysis of ovarian development between 8 and 20 wk gestation was performed.
MAIN OUTCOME MEASURE(S): The expression patterns of PG synthesis enzymes and the PGE(2) receptors EP2 and EP4 in the ovary were assessed, and downstream effects of PGE(2) on gene expression were analyzed.
RESULTS: Ovarian germ cells express the PG synthetic enzymes COX2 and PTGES as well as the EP2 and EP4 receptors, whereas COX1 is expressed by ovarian somatic cells. Treatment in vitro with PGE(2) increased the expression of BDNF mRNA 1.7 +/- 0.16-fold (P = 0.004); INHBA mRNA, 2.1 +/- 0.51-fold (P = 0.04); and MCL1 mRNA, 1.15 +/- 0.06-fold (P = 0.04), but not that of OCT4, DAZL, VASA, NTF5, or SMAD3.
CONCLUSIONS: These data indicate novel roles for PGE(2) in the regulation of germ cell development in the human ovary and show that these effects may be mediated by the regulation of factors including BDNF, activin A, and MCL1.
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Aims. We present rates for all E1, E2, M1, and M2 transitions among the 295 fine-structure levels of the configurations 3d9, 3d84s, 3d74s2, 3d84p, and 3d74s4p, determined through an extensive configuration interaction calculation.
Methods. The CIV3 code developed by Hibbert and coworkers is used to determine for these levels configuration interaction wave functions with relativistic effects introduced through the Breit-Pauli approximation.
Results. Two different sets of calculations have been undertaken with different 3d and 4d functions to ascertain the effect of such variation. The main body of the text includes a representative selection of data, chosen so that key points can be discussed. Some analysis to assess the accuracy of the present data has been undertaken, including comparison with earlier calculations and the more limited range of experimental determinations. The full set of transition data is given in the supplementary material as it is very extensive.
Conclusions. We believe that the present transition data are the best currently available.
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1 kartta :, vär. ;, 51,1 x 43 cm, lehti 58 x 50,4 cm