• 【监管空间与常见功能压力的情境中介: 分析导致德国效率前沿方法的因素。】 复制标题 收藏 收藏
    DOI:10.1016/j.healthpol.2013.01.004 复制DOI
    作者列表:Klingler C,Shah SM,Barron AJ,Wright JS
    BACKGROUND & AIMS: :There are no automatic links between the functional advantages and pressures associated with delegation to independent agencies for Health Technology Assessment (HTA) and their emergence in national regulatory spaces. We argue that the rise of these organizations is mediated by contextual factors, which must be explained. Accordingly, we analyze the German 'regulatory space' for health policy decision-making, identifying contextual factors relevant to the adoption of the Efficiency Frontier approach. Based on qualitative interviews with key stakeholders, we argue that the development of the Efficiency Frontier can be associated with cultural reluctance to frame healthcare prioritization decisions around cost based valuations of human health and related doubts about the validity of metrics for human health gain. Based on this finding, we conclude that the delegation of authority to independent HTA agencies follows a broadly evolutionary pattern, in which contextual factors allow for significant variation in institutional and methodological responses to the functional pressures and advantages leading to their establishment.
    背景与目标: : 与授权给独立的卫生技术评估机构 (HTA) 相关的功能优势和压力与它们在国家监管空间中的出现之间没有自动联系。我们认为,这些组织的兴起是由上下文因素介导的,必须对此进行解释。因此,我们分析了德国卫生政策决策的 “监管空间”,确定了与采用效率前沿方法有关的背景因素。基于对主要利益相关者的定性访谈,我们认为效率边界的发展可能与文化上不愿围绕基于成本的人类健康评估制定医疗保健优先决策以及对人类健康收益指标有效性的相关怀疑有关。基于这一发现,我们得出结论,将权力下放给独立的HTA机构遵循一种广泛的进化模式,在这种模式下,背景因素允许机构和方法对导致其建立的功能压力和优势的反应发生重大变化。
  • 【慢性伤口患者的经济压力,社会支持,年龄和生活质量之间的关系: 一个适度的中介模型。】 复制标题 收藏 收藏
    DOI:10.1111/jan.14413 复制DOI
    作者列表:Ren H,Ding Y,Hu H,Gao T,Qin Z,Hu Y,Cao R,Liang L,Li C,Mei S
    BACKGROUND & AIMS: AIMS:The aims of this study were as follows: (a) to determine if social support mediates the relationship between economic stress and quality of life; and (b) to explore whether participants' ages would moderate the indirect relationship between economic stress and quality of life through social support. DESIGN:A questionnaire-based, cross-sectional study. METHODS:From January 2015-June 2016, a total of 300 patients with chronic wounds were recruited from three hospitals. Data regarding economic stress, social support and quality of life were collected through survey questionnaires. The moderated mediation analysis was examined using the Hayes' PROCESS macro modelling tool, based on the bias-corrected bootstrapping method. RESULTS:Economic stress was negatively correlated with quality of life and social support. The indirect effect of economic stress on quality of life through social support was negative. Furthermore, age moderated the relationship between economic stress and quality of life, as well as the relationship between economic stress and social support. CONCLUSION:Reducing economic stress and improving social support are important strategies for improving quality of life in patients with chronic wounds, especially for younger patients. IMPACT:Patients with chronic wounds experience considerable economic stress and severely impaired quality of life; however, little is known about the inner mechanisms of this relationship. This study emphasized the importance of providing social support in coping with the damage that economic stress causes to health. Clinical nurses should strengthen the comprehensive assessment of the socioeconomic status of patients and adjust nursing plans timely, to reduce the economic burden of patients based on the rational use of wound care materials. Moreover, when nursing for patients with chronic wounds, especially the elders, caregivers should strengthen the evaluation of social support and develop interventions to improve social support.
    背景与目标:
  • 【Maslinic酸抑制DU145人前列腺癌细胞的转移能力: 可能通过缺氧诱导因子-1α 信号介导。】 复制标题 收藏 收藏
    DOI:10.1017/S0007114512000967 复制DOI
    作者列表:Park SY,Nho CW,Kwon DY,Kang YH,Lee KW,Park JH
    BACKGROUND & AIMS: :Maslinic acid is found in various natural sources, most notably in pomace olive oil, and exerts pro-apoptotic activities in various cancer cells in vitro. In the present study, DU145 human prostate cancer cells were cultured with 0-25 μm-maslinic acid to examine the effects of maslinic acid on the metastatic capacity of prostate cancer cells. Maslinic acid significantly (P <0.05) inhibited the basal and epidermal growth factor (EGF)-induced migration (27-64 %), invasion (23-60 %) and adhesion (8-40 %) of DU145 cells. Maslinic acid significantly (P <0·05) down-regulated both basal and EGF-stimulated secretion of matrix metalloproteinase (MMP)-9 (25-67 %), MMP-2 (50-86 %), urokinase-type plasminogen activator (uPA, about 100 %), vascular endothelial growth factor (VEGF, 98-100 %) and tissue inhibitors of metalloproteinases (TIMP)-1, as well as expression of uPA receptor (uPAR), intercellular adhesion molecules (22-33 %), vascular cell adhesion molecules (23-46 %) and E-cadherin, whereas it increased TIMP-2 secretion. Maslinic acid dramatically reduced the levels of hypoxia-inducible factor-1α (HIF-1α) protein and mRNA; the reduction was accompanied by reduced stability, nuclear levels and transcriptional activity of HIF-1α. The levels of phospho-Akt and phospho-extracellular signal-related kinase (ERK) were reduced in cells treated with maslinic acid, and the phosphoinositide 3-kinase inhibitor LY294002 and the mitogen-activated protein kinase kinase inhibitor PD98059 reduced HIF-1α levels and VEGF secretion. The results show that maslinic acid markedly inhibited the migration, invasion and adhesion of DU145 prostate cancer cells. Suppressing HIF-1α activation by inhibiting Akt and ERK activation may be part of the mechanism by which maslinic acid inhibited uPAR, E-cadherin, VEGF and MMP expression in DU145 cells.
    背景与目标: : Maslinic酸存在于各种天然来源中,最显着的是果渣橄榄油中,并在体外在各种癌细胞中发挥促凋亡活性。在本研究中,用0-25μm-maslinic酸培养DU145人前列腺癌细胞,以检查maslinic酸对前列腺癌细胞转移能力的影响。大西林酸显著 (P <0.05) 抑制基底和表皮生长因子 (EGF) 诱导的DU145细胞迁移 (27-64%) 、侵袭 (23-60%) 和粘附 (8-40%)。山麦酸显著 (P & lt; 0.05) 下调基质金属蛋白酶-9 (25-67%) 、MMP-2 (50-86%) 、尿激酶型纤溶酶原激活物 (uPA,约100%) 、血管内皮生长因子 (VEGF,98-100%) 和金属蛋白酶 (TIMP)-1的组织抑制剂,以及uPA受体 (uPAR),细胞间粘附分子 (22-33%),血管细胞粘附分子 (23-46%) 和E-钙粘蛋白的表达,而它增加了TIMP-2分泌。Maslinic酸显着降低了缺氧诱导因子-1α (HIF-1α) 蛋白和mRNA的水平; 降低伴随着HIF-1α 的稳定性,核水平和转录活性降低。在用山糖酸处理的细胞中,磷酸-Akt和磷酸-细胞外信号相关激酶 (ERK) 的水平降低,磷酸肌醇3-激酶抑制剂LY294002和丝裂原活化蛋白激酶抑制剂PD98059降低了HIF-1α 水平和VEGF分泌。结果表明,大西林酸可明显抑制DU145前列腺癌细胞的迁移、侵袭和粘附。通过抑制Akt和ERK激活来抑制HIF-1α 激活可能是maslinic酸抑制DU145细胞中uPAR,E-cadherin,VEGF和MMP表达的部分机制。
  • 【孕产妇BMI介导了巴基斯坦农村地区怀孕期间与作物相关的农业工作对婴儿长度的影响: 横断面数据的中介分析。】 复制标题 收藏 收藏
    DOI:10.1186/s12884-019-2638-3 复制DOI
    作者列表:Pradeilles R,Allen E,Gazdar H,Bux Mallah H,Budhani A,Mehmood R,Mazhar S,Mysorewala A,Aslam S,Dangour AD,Ferguson E
    BACKGROUND & AIMS: BACKGROUND:Stunted growth in early infancy is a public health problem in low-and-middle income countries. Evidence suggests heavy agricultural work during pregnancy is inversely associated with maternal body mass index (BMI) and infant birth weight in low- and middle-income countries; but pathways linking agricultural work to length-for-age Z-scores (LAZ) in early infancy have not been examined. This study aimed to investigate the relationship between agricultural work during pregnancy, post-natal maternal BMI and LAZ among young infants in rural Pakistan; and explored whether maternal BMI mediated the relationship between agricultural work and infant LAZ. METHODS:A cross-sectional survey was conducted from December 2015 to January 2016 in rural Sindh, Pakistan. Mother-infant dyads were recruited via systematic random cluster sampling at 2-12 weeks' post-partum (n = 1161). Anthropometric measurements (maternal and infant height/length and weight) and questionnaire data were collected. Multivariable linear regression and structural-equation based mediation analyses were used to examine associations of agricultural work during pregnancy with maternal BMI and infant LAZ. RESULTS:During pregnancy, women reported engaging in livestock-related work (57.0%), crop-related work (42.7%), and cotton harvesting (28.4%). All three forms of agricultural work were negatively associated with maternal BMI (β = - 0.67 [- 1.06; - 0.28], β = - 0.97 [- 1.51; - 0.48]; and β = - 0.87 [- 1.33; - 0.45], respectively). Maternal engagement in cotton harvesting alone was negatively associated with infant LAZ after controlling for confounding factors. The total negative effect of cotton harvesting on infant LAZ was - 0.35 [- 0.53; - 0.16]. The indirect effect of maternal BMI on infant LAZ was - 0.06 [- 0.08; - 0.03], revealing that 16% (- 0.06/- 0.35) of the relationship between cotton harvesting and infant LAZ, after adjustment, was mediated via maternal BMI. CONCLUSION:These results underscore a need to reduce labour-intensive agricultural workload demands during pregnancy, especially in cotton harvesting, to reduce risks of negative maternal energy balance and poor growth outcomes in early infancy.
    背景与目标:
  • 【钨酸盐和钼酸盐的胰岛素样作用: 通过胰岛素受体独立途径介导。】 复制标题 收藏 收藏
    DOI:10.1007/BF02746339 复制DOI
    作者列表:Li J,Elberg G,Libman J,Shanzer A,Cefel D,Shechter Y
    BACKGROUND & AIMS: :The insulin-like effects of tungstate (W) and molybdate (Mo) were studied in rat adipocytes and compared to those of vanadate. Other than being less potent, W and Mo resembled vanadate in stimulating lipogenesis, in activating glucose oxidation, in enhancing rate of hexose uptake, and in inhibiting lipolysis. Tungstate and molybdate did not activate the insulinreceptor tyrosine kinase (InsRTK). Quercetin which blocks InsRTK activity and insulin stimulation of glucose metabolism, failed to inhibit when these bioeffects were stimulated by W or Mo. The metalooxide, however, activated a staurosporine sensitive non receptor, cytosolic protein tyrosine kinase (CytPTK), and staurosporine blocked W or Mo dependent lipogenesis in rat adipocytes. Staurosporine did not prevent Mo and W either from activating hexose transport, or from inhibiting lipolysis. Tungstate and molybdate were less effective than vanadate in inhibiting adipose PTPases in cell free systems. Membranal PTPases were more sensitive to W and Mo inhibition than cytosolic PTPases. While the presence of a nucleophile such as hydroxylamine reversed inhibition of PTPase by vanadate it did not affect inhibition by W or Mo. In summary, the insulinomimetic effects of W and Mo appear to resemble qualitatively that of vanadate in all respects. Both act in an insulin receptor-independent-fashion, activate CytPTK and trigger additional effects that are not mediated by the InsRTK or by CytPTK. The quantitative differences may be attributed to reduced capacity of W and Mo relative to vanadate to inhibit the relevant PTPases in intact cells.
    背景与目标: : 在大鼠脂肪细胞中研究了钨酸盐 (W) 和钼酸盐 (Mo) 的胰岛素样作用,并与钒酸盐进行了比较。除了效力较弱之外,W和Mo在刺激脂肪生成,激活葡萄糖氧化,提高己糖摄取率和抑制脂解作用方面类似于钒酸盐。钨酸盐和钼酸盐不会激活胰岛素受体酪氨酸激酶 (InsRTK)。槲皮素可阻断InsRTK活性和胰岛素刺激葡萄糖代谢,但当W或Mo刺激这些生物效应时,槲皮素无法抑制。然而,金属氧化物激活了星形孢菌素敏感的非受体,胞质蛋白酪氨酸激酶 (cyptk),星形孢菌素阻断了大鼠脂肪细胞中W或Mo依赖性脂肪生成。星形孢菌素不能阻止Mo和W激活己糖转运或抑制脂解。钨酸盐和钼酸盐在抑制无细胞系统中的脂肪PTPases的效果不如钒酸盐。膜al PTPases对W和Mo抑制比胞质PTPases更敏感。虽然亲核试剂 (例如羟胺) 的存在使钒酸盐对PTPase的抑制作用逆转,但不会影响W或Mo的抑制作用。总而言之,W和Mo的胰岛素模拟作用在所有方面都与钒酸盐的定性相似。两者均以不依赖胰岛素受体的方式起作用,激活cyptk并触发InsRTK或cyptk未介导的其他作用。定量差异可能归因于W和Mo相对于钒酸盐抑制完整细胞中相关PTPases的能力降低。
  • 【青少年常规赌徒适应不良人格特征与正念缺陷之间的相互作用: 一种中介模型。】 复制标题 收藏 收藏
    DOI:10.1007/s10899-018-9811-x 复制DOI
    作者列表:Passanisi A,D'Urso G,Pace U
    BACKGROUND & AIMS: :Authors aimed to examine an explanatory model of risk that started with dysfunctional personality trait domains, passed through low levels of mindfulness, and culminated with problem gambling. For individuals with problem gambling, mindfulness may provide a significant avenue to prevent them from engaging in addictive behaviors and lead them to an improved sense of self-control and emotion regulation. We employed a mediation analysis design assessing 326 Caucasian adolescent regular gamblers ranging in age from 15 to 17 years who were recruited in betting or bingo halls. Using the Personality Inventory for DSM-5-Brief Form (PID-5-BF)-Children, the South Oaks Gambling Screen, and the Child and Adolescent Mindfulness Measure, we examined the hypothesis that low levels of mindfulness partially mediate the relationship between dysfunctional personality trait domains and problem gambling. The findings underline the role that may play by the core skills of mindfulness. Indeed, results suggest how adolescents with personalities characterized by antagonism, disinhibition, and negative affectivity may tend toward a lack of awareness of self-related mental states and difficulty purposefully regulating attention and dealing with negative emotions that predispose them to gambling as a means of escape from uncomfortable feelings.
    背景与目标: : 作者旨在研究一种风险解释模型,该模型始于功能失调的人格特质领域,通过低正念水平,最终以问题赌博告终。对于有问题赌博的人来说,正念可能提供一个重要的途径来防止他们从事上瘾的行为,并导致他们提高自我控制和情绪调节的意识。我们采用了中介分析设计,评估了326名在博彩或宾果游戏大厅招募的年龄在15至17岁之间的白人青少年常规赌徒。使用DSM-5-Brief形式 (PID-5-BF) 的人格清单-儿童,南橡树赌博屏幕以及儿童和青少年正念措施,我们检验了以下假设: 低正念水平部分介导了功能失调的人格特质域与问题赌博之间的关系。研究结果强调了正念的核心技能可能扮演的角色。实际上,结果表明,具有以对抗,抑制和消极情感为特征的个性的青少年可能会倾向于缺乏对自我相关的心理状态的认识,并且难以有目的地调节注意力并处理使他们容易赌博的负面情绪。摆脱不舒服的感觉。
  • 【小样本量研究中基于置换的中介分析方法。】 复制标题 收藏 收藏
    DOI:10.7717/peerj.8246 复制DOI
    作者列表:Kroehl ME,Lutz S,Wagner BD
    BACKGROUND & AIMS: Background:Mediation analysis can be used to evaluate the effect of an exposure on an outcome acting through an intermediate variable or mediator. For studies with small sample sizes, permutation testing may be useful in evaluating the indirect effect (i.e., the effect of exposure on the outcome through the mediator) while maintaining the appropriate type I error rate. For mediation analysis in studies with small sample sizes, existing permutation testing methods permute the residuals under the full or alternative model, but have not been evaluated under situations where covariates are included. In this article, we consider and evaluate two additional permutation approaches for testing the indirect effect in mediation analysis based on permutating the residuals under the reduced or null model which allows for the inclusion of covariates. Methods:Simulation studies were used to empirically evaluate the behavior of these two additional approaches: (1) the permutation test of the Indirect Effect under Reduced Models (IERM) and (2) the Permutation Supremum test under Reduced Models (PSRM). The performance of these methods was compared to the standard permutation approach for mediation analysis, the permutation test of the Indirect Effect under Full Models (IEFM). We evaluated the type 1 error rates and power of these methods in the presence of covariates since mediation analysis assumes no unmeasured confounders of the exposure-mediator-outcome relationships. Results:The proposed PSRM approach maintained type I error rates below nominal levels under all conditions, while the proposed IERM approach exhibited grossly inflated type I rates in many conditions and the standard IEFM exhibited inflated type I error rates under a small number of conditions. Power did not differ substantially between the proposed PSRM approach and the standard IEFM approach. Conclusions:The proposed PSRM approach is recommended over the existing IEFM approach for mediation analysis in studies with small sample sizes.
    背景与目标:
  • 【路径中介分析显示,GBA通过增加 α-突触核蛋白水平来影响路易身体疾病状况。】 复制标题 收藏 收藏
    DOI:10.1016/j.nbd.2018.09.015 复制DOI
    作者列表:Gündner AL,Duran-Pacheco G,Zimmermann S,Ruf I,Moors T,Baumann K,Jagasia R,van de Berg WDJ,Kremer T
    BACKGROUND & AIMS: :Synucleinopathies including Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are characterized by the accumulation of abnormal α-synuclein in intraneuronal inclusions, named Lewy bodies. Mutations in GBA1, the gene encoding the lysosomal hydrolase glucocerebrosidase, have been identified as the most common genetic risk factor for PD and DLB. However, despite extensive research, the mechanism by which glucocerebrosidase dysfunction increases the risk for PD or DLB still remains elusive. In our study we expand the toolbox for PD-DLB post-mortem studies by introducing new quantitative biochemical assays for glucocerebrosidase and α-synuclein. Applying causal modelling, we determine how these parameters are interrelated and ultimately impact disease manifestation. We developed quantitative immuno-based assays for glucocerebrosidase and α-synuclein (total and phosphorylated at Serine 129) protein levels, as well as a liquid chromatography-mass spectrometry method for the detection of the glucocerebrosidase lipid substrate glucosylsphingosine. These assays were applied on tissue samples from frontal cortex, putamen and substantia nigra of PD (n = 15) and DLB (n = 15) patients and age-matched non-demented controls (n = 15). Our results confirm elevated p-129 over total α-synuclein levels in the insoluble fraction of PD and DLB post-mortem brain tissue and we found significantly increased α-synuclein levels in the soluble fractions in PD and DLB. Furthermore, we identified an inverse correlation between reduced glucocerebrosidase enzyme activity and protein levels with increased glucosylsphingosine levels. In the substantia nigra, a brain region particularly vulnerable in Parkinson's disease, we found a significant correlation between glucocerebrosidase protein reduction and increased p129/total α-synuclein ratios. We assessed the direction and strength of the interrelation between all measured parameters by confirmatory path analysis. Interestingly, we found that glucocerebrosidase dysfunction impacts the PD-DLB status by increasing α-synuclein ratios in the substantia nigra, which was partly mediated by increasing glucosylsphingosine levels. In conclusion, we show that the introduced immuno-based assays enable the quantitative assessment of glucocerebrosidase and α-synuclein parameters in post-mortem brain. In the substantia nigra, reduced glucocerebrosidase levels contribute to the increase in α-synuclein levels and to PD-DLB disease manifestation partly by increasing its glycolipid substrate glucosylsphingosine. This interrelation between glucocerebrosidase, glucosylsphingosine and α-synuclein parameters supports the hypothesis that glucocerebrosidase acts as a modulator of PD-DLB.
    背景与目标: : 包括帕金森氏病 (PD) 和路易体痴呆 (DLB) 在内的突触核蛋白病的特征是神经内包裹体 (称为路易体) 中异常 α-突触核蛋白的积累。编码溶酶体水解酶葡萄糖脑苷脂酶的基因GBA1的突变已被确定为PD和DLB最常见的遗传危险因素。然而,尽管进行了广泛的研究,但葡萄糖脑苷脂酶功能障碍增加PD或DLB风险的机制仍然难以捉摸。在我们的研究中,我们通过引入葡萄糖脑苷脂酶和 α-突触核蛋白的新的定量生化测定法,扩展了pd-dlb死后研究的工具箱。应用因果模型,我们确定这些参数是如何相互关联并最终影响疾病表现的。我们开发了基于定量免疫的葡萄糖脑苷脂酶和 α-突触核蛋白 (在丝氨酸129下全部和磷酸化) 蛋白水平的检测方法,以及用于检测葡萄糖脑苷脂酶脂质底物葡萄糖鞘氨醇的液相色谱-质谱方法。这些检测方法应用于PD (n   =   15) 和DLB (n   =   15) 患者的额叶皮层,壳核和黑质的组织样本以及年龄匹配的非痴呆对照组 (n   =   15)。我们的结果证实,在PD和DLB死后脑组织的不溶性部分中,相对于总 α-突触核蛋白水平的p-129升高,并且我们发现PD和DLB中可溶性部分中的 α-突触核蛋白水平显着增加。此外,我们确定了葡萄糖脑苷脂酶活性降低与蛋白质水平与葡萄糖鞘氨醇水平升高之间的负相关。在黑质 (在帕金森氏病中特别脆弱的大脑区域) 中,我们发现葡萄糖脑苷脂酶蛋白减少与p129/总 α-突触核蛋白比率增加之间存在显着相关性。我们通过验证性路径分析评估了所有测量参数之间相互关系的方向和强度。有趣的是,我们发现葡萄糖脑苷脂酶功能障碍通过增加黑质中的 α-突触核蛋白比率来影响PD-DLB状态,这部分是通过增加葡萄糖鞘氨醇水平来介导的。总之,我们表明引入的基于免疫的测定法能够定量评估死后大脑中的葡萄糖脑苷脂酶和 α-突触核蛋白参数。在黑质中,葡萄糖脑苷脂酶水平的降低部分通过增加其糖脂底物葡萄糖基鞘氨醇而导致 α-突触核蛋白水平的增加和PD-DLB疾病的表现。葡萄糖脑苷脂酶,葡萄糖鞘氨醇和 α-突触核蛋白参数之间的这种相互关系支持了葡萄糖脑苷脂酶充当pd-dlb调节剂的假说。
  • 【因果关系与传统中介分析的对应关系: 联系是治疗互动的中介。】 复制标题 收藏 收藏
    DOI:10.1007/s11121-019-01076-4 复制DOI
    作者列表:MacKinnon DP,Valente MJ,Gonzalez O
    BACKGROUND & AIMS: :Mediation analysis is a methodology used to understand how and why behavioral phenomena occur. New mediation methods based on the potential outcomes framework are a seminal advancement for mediation analysis because they focus on the causal basis of mediation. Despite the importance of the potential outcomes framework in other fields, the methods are not well known in prevention and other disciplines. The interaction of a treatment (X) and a mediator (M) on an outcome variable (Y) is central to the potential outcomes framework for causal mediation analysis and provides a way to link traditional and modern causal mediation methods. As described in the paper, for a continuous mediator and outcome, if the XM interaction is zero, then potential outcomes estimators of the mediated effect are equal to the traditional model estimators. If the XM interaction is nonzero, the potential outcomes estimators correspond to simple direct and simple mediated contrasts for the treatment and the control groups in traditional mediation analysis. Links between traditional and causal mediation estimators clarify the meaning of potential outcomes framework mediation quantities. A simulation study demonstrates that testing for a XM interaction that is zero in the population can reduce power to detect mediated effects, and ignoring a nonzero XM interaction in the population can also reduce power to detect mediated effects in some situations. We recommend that prevention scientists incorporate evaluation of the XM interaction in their research.
    背景与目标: : 中介分析是一种用于理解行为现象发生的方式和原因的方法。基于潜在结果框架的新调解方法是调解分析的开创性进展,因为它们侧重于调解的因果基础。尽管潜在结果框架在其他领域很重要,但在预防和其他学科中,这些方法并不为人所知。治疗 (X) 和中介 (M) 对结果变量 (Y) 的相互作用是因果中介分析的潜在结果框架的核心,并提供了一种将传统和现代因果中介方法联系起来的方法。如本文所述,对于连续的中介和结果,如果XM相互作用为零,则中介效应的潜在结果估计量等于传统的模型估计量。如果XM相互作用非零,则在传统中介分析中,潜在的结果估计量对应于治疗组和对照组的简单直接和简单介导的对比。传统中介估计量和因果中介估计量之间的联系阐明了潜在结果框架中介量的含义。模拟研究表明,对人群中为零的XM相互作用进行测试可以降低检测中介效应的能力,而忽略人群中非零的XM相互作用也可以降低在某些情况下检测中介效应的能力。我们建议预防科学家在研究中纳入对XM相互作用的评估。
  • 【大学生虐待儿童和自伤: 测试冲动的调解和适度模型。】 复制标题 收藏 收藏
    DOI:10.1111/j.1939-0025.2012.01165.x 复制DOI
    作者列表:Arens AM,Gaher RM,Simons JS
    BACKGROUND & AIMS: :This study examined the relationship between child maltreatment, impulsivity, and deliberate self-harm in a sample of college students. Four subtypes of impulsivity (urgency, premeditation, perseverance, and sensation seeking) were examined. Results show that participants who report child maltreatment histories also report higher levels of negative affect and higher levels of impulsivity, specifically negative urgency. In addition, those who report histories of child maltreatment are more likely to endorse deliberate self-harm behaviors as an adult. Of the 4 subtypes of impulsivity, urgency was most strongly related to deliberate self-harm. Urgency, but not the other subtypes of impulsivity, mediated the relationship between child maltreatment and self-harm. The current study contributes to the understanding of the mechanisms behind deliberate self-harm behavior by suggesting that individuals with histories of child maltreatment are more likely to engage in deliberate self-harm in an attempt to quickly reduce intense negative affect.
    背景与目标: : 这项研究调查了大学生样本中虐待儿童,冲动和自伤之间的关系。检查了冲动的四种亚型 (紧迫感,预谋,毅力和寻求感觉)。结果表明,报告儿童虐待史的参与者还报告了较高水平的负面影响和较高水平的冲动性,特别是负面紧迫性。此外,那些报告虐待儿童史的人更有可能认可成年后的自伤行为。在冲动的4种亚型中,紧迫感与自伤关系最密切。紧迫性,而不是冲动性的其他亚型,介导了虐待儿童和自我伤害之间的关系。当前的研究表明,有虐待儿童史的人更有可能参与自伤,以试图迅速减少强烈的负面影响,从而有助于理解自伤行为背后的机制。
  • 【久坐时间,代谢异常和心肌梗死后全因死亡率: 中介分析。】 复制标题 收藏 收藏
    DOI:10.1177/2047487318804611 复制DOI
    作者列表:Wu Z,Huang Z,Wu Y,Huang S,Wang Y,Zhao H,Chen S,Wu S,Gao X
    BACKGROUND & AIMS: BACKGROUND:Sedentary time was associated with myocardial infarction (MI) and metabolic diseases in previous studies. PURPOSE:To investigate whether sedentary time measured before disease onset was associated with all-cause mortality among MI survivors and whether the sedentary time-mortality association was mediated by physical activity status and metabolic phenotypes. METHODS:In this prospective community-based cohort including 101,510 Chinese adults, we used sedentary time, evaluated at 2006 (baseline), to predict further all-cause mortality among individuals who then developed new onset MI from 2006 to December 2013 ( n = 989). The post-MI mortality was ascertained after the first non-fatal MI until December 2014. We assessed the mediating effects of physical inactivity and metabolic factors on the sedentary time-mortality association. RESULTS:During 7 years follow up, 180 deaths occurred among these participants with incident MI. Prolonged sedentary time was associated with a higher risk of mortality among MI survivors. The adjusted hazard ratio (HR) of mortality for sedentary time 4-8 hours/day versus <4 hours/day, was 1.62 (95% confidence interval (CI) 1.14-2.31). A high amount of sedentary time (>4 hours/day) and inactive physical activity had an increased risk of all-cause mortality (HR: 2.74, 95% CI 1.34-5.60), relative to those with sedentary time ≤4 hours/day and moderate/vigorous physical activity. Physical inactivity and metabolic factors mediated a small proportion (≤9.2 % for all) of the total association between sedentary time and post-MI mortality. CONCLUSION:High sedentary time was significantly associated with all-cause mortality among MI survivors, independent of physical activity status and metabolic abnormalities.
    背景与目标:
  • 【醛糖还原酶在脂多糖诱导的小鼠腹膜巨噬细胞炎症信号中的介导。】 复制标题 收藏 收藏
    DOI:10.1016/j.cyto.2006.11.003 复制DOI
    作者列表:Ramana KV,Srivastava SK
    BACKGROUND & AIMS: :Aldose reductase (AR; AKR1B1) a member of aldo-keto reductase super family, that we had shown earlier mediates cytotoxic signals induced by high glucose, cytokines and growth factors, also mediates the inflammatory signals induced by Gram-negative bacterial endotoxin, lipopolysaccharide (LPS). Inhibition of AR by three distinct AR inhibitors sorbinil, tolrestat or zopolrestat suppressed the LPS-induced production of inflammatory cytokines such as TNF-alpha, IL-6, IL-1beta, IFN-gamma, and chemokine MCP-1 in murine peritoneal macrophages. Inhibition of AR also prevented the production of nitric oxide, and prostaglandin E2 and expression of iNOS and Cox-2 proteins. The LPS-induced DNA binding activity of NF-kappaB and AP1 were significantly inhibited by AR inhibitors, and this effect was mediated through the inhibition of phosphorylation of IkappaB-alpha, IKK alpha/beta and PKC. These results suggest the therapeutic use of AR inhibitors as anti-inflammatory drugs.
    背景与目标: : 醛糖还原酶 (AR; AKR1B1) 是aldo-酮还原酶超级家族的成员,我们已经显示出较早的介导高糖,细胞因子和生长因子诱导的细胞毒性信号,也介导革兰氏阴性细菌内毒素,脂多糖 (LPS) 诱导的炎症信号。三种不同的AR抑制剂sorbinil,tolrestat或zopolrestat对AR的抑制作用抑制了LPS诱导的炎症细胞因子的产生,例如TNF-α,IL-6,IL-1beta,IFN-γ 和小鼠腹膜巨噬细胞中的趋化因子MCP-1。抑制AR还阻止了一氧化氮和前列腺素E2的产生以及iNOS和Cox-2蛋白的表达。AR抑制剂显著抑制了LPS诱导的NF-κ b和AP1的DNA结合活性,并且这种作用是通过抑制IkappaB-α,IKK α/β 和PKC的磷酸化来介导的。这些结果表明AR抑制剂作为抗炎药的治疗用途。
  • 【神经肽Y抑制分离的豚鼠结肠中的胆碱能传递: 通过 α-肾上腺素能受体介导。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.84.7.2047 复制DOI
    作者列表:Wiley J,Owyang C
    BACKGROUND & AIMS: :Neuropeptide Y, a member of the pancreatic polypeptide family, caused dose-dependent relaxation of guinea pig colon longitudinal muscle. This inhibitory effect was unaffected by hexamethonium but was abolished by atropine and tetrodotoxin, suggesting that neuropeptide Y is acting via postganglionic cholinergic neurons. Studies utilizing alpha-adrenergic and dopamine receptor antagonists revealed that neuropeptide Y-mediated relaxation was blocked only by the alpha 2 antagonist yohimbine. Neuropeptide Y also antagonized muscle response to electric field stimulation that was reversed by yohimbine. Additional studies with muscle slices incubated with [3H]norepinephrine or [3H]choline showed that neuropeptide Y stimulated norepinephrine release from sympathetic nerves, which, in turn, inhibited the release of acetylcholine via alpha 2 receptors located on postganglionic nerves. This pathway provides a mechanism for neuropeptide modulation of classical neurotransmitter function.
    背景与目标: : 神经肽Y是胰多肽家族的成员,引起豚鼠结肠纵向肌的剂量依赖性松弛。这种抑制作用不受六甲铵的影响,但被阿托品和河豚毒素消除,表明神经肽Y通过神经节后胆碱能神经元起作用。利用 α-肾上腺素能和多巴胺受体拮抗剂的研究表明,神经肽Y介导的松弛仅被 α2拮抗剂育亨宾阻断。神经肽Y还拮抗肌肉对电场刺激的反应,育亨宾可以逆转这种反应。用 [3H] 去甲肾上腺素或 [3H] 胆碱孵育的肌肉切片的其他研究表明,神经肽Y刺激了去甲肾上腺素从交感神经的释放,进而,通过位于节后神经上的 α2受体抑制乙酰胆碱的释放,该途径为神经肽调节经典神经递质功能提供了机制。
  • 【加速失效时间模型下截尾生存数据的中介分析。】 复制标题 收藏 收藏
    DOI:10.1097/EDE.0000000000000687 复制DOI
    作者列表:Fulcher IR,Tchetgen Tchetgen EJ,Williams PL
    BACKGROUND & AIMS: :Recent advances in causal mediation analysis have formalized conditions for estimating direct and indirect effects in various contexts. These approaches have been extended to a number of models for survival outcomes including accelerated failure time models, which are widely used in a broad range of health applications given their intuitive interpretation. In this setting, it has been suggested that under standard assumptions, the "difference" and "product" methods produce equivalent estimates of the indirect effect of exposure on the survival outcome. We formally show that these two methods may produce substantially different estimates in the presence of censoring or truncation, due to a form of model misspecification. Specifically, we establish that while the product method remains valid under standard assumptions in the presence of independent censoring, the difference method can be biased in the presence of such censoring whenever the error distribution of the accelerated failure time model fails to be collapsible upon marginalizing over the mediator. This will invariably be the case for most choices of mediator and outcome error distributions. A notable exception arises in case of normal mediator-normal outcome where we show consistency of both difference and product estimators in the presence of independent censoring. These results are confirmed in simulation studies and two data applications.
    背景与目标: : 因果中介分析的最新进展正式确定了在各种情况下估计直接和间接影响的条件。这些方法已扩展到许多生存结果模型,包括加速失效时间模型,鉴于其直观的解释,这些模型已广泛用于广泛的健康应用中。在这种情况下,有人建议在标准假设下,“差异” 和 “乘积” 方法对暴露对生存结果的间接影响产生等效估计。我们正式证明,由于某种形式的模型错误指定,在存在审查或截断的情况下,这两种方法可能会产生实质上不同的估计。具体来说,我们确定,尽管在存在独立审查的情况下,在标准假设下,乘积方法仍然有效,但在存在这种审查的情况下,只要加速失效时间模型的误差分布在中介机构上被边缘化时无法折叠,差异方法就会产生偏差。对于大多数中介和结果错误分布的选择,情况总是如此。在正常中介-正常结果的情况下,出现了一个值得注意的例外,在这种情况下,我们在存在独立审查的情况下显示了差异估计和乘积估计的一致性。这些结果在仿真研究和两个数据应用中得到了证实。
  • 【Β3-肾上腺素诱导的棕色脂肪组织中的葡萄糖摄取与UCP1的存在或活性无关: 通过mTOR途径介导。】 复制标题 收藏 收藏
    DOI:10.1016/j.molmet.2017.02.006 复制DOI
    作者列表:Olsen JM,Csikasz RI,Dehvari N,Lu L,Sandström A,Öberg AI,Nedergaard J,Stone-Elander S,Bengtsson T
    BACKGROUND & AIMS: OBJECTIVE:Today, the presence and activity of brown adipose tissue (BAT) in adult humans is generally equated with the induced accumulation of [2-18F]2-fluoro-2-deoxy-d-glucose ([18F]FDG) in adipose tissues, as investigated by positron emission tomography (PET) scanning. In reality, PET-FDG is currently the only method available for in vivo quantification of BAT activity in adult humans. The underlying assumption is that the glucose uptake reflects the thermogenic activity of the tissue. METHODS:To examine this basic assumption, we here followed [18F]FDG uptake by PET and by tissue [3H]-2-deoxy-d-glucose uptake in wildtype and UCP1(-/-) mice, i.e. in mice that do or do not possess the unique thermogenic and calorie-consuming ability of BAT. RESULTS:Unexpectedly, we found that β3-adrenergically induced (by CL-316,243) glucose uptake was UCP1-independent. Thus, whereas PET-FDG scans adequately reflect glucose uptake, this acute glucose uptake is not secondary to thermogenesis but is governed by an independent cellular signalling, here demonstrated to be mediated via the previously described KU-0063794-sensitive mTOR pathway. CONCLUSIONS:Thus, PET-FDG scans do not exclusively reveal active BAT deposits but rather any tissue possessing an adrenergically-mediated glucose uptake pathway. In contrast, we found that the marked glucose uptake-ameliorating effect of prolonged β3-adrenergic treatment was UCP1 dependent. Thus, therapeutically, UCP1 activity is required for any anti-diabetic effect of BAT activation.
    背景与目标:

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