Investigating the ‘placebo personality’ outside the pain paradigm

Aim

To identify personality traits related to placebo responding outside the context of pain.

Methods

Sixty three healthy volunteers completed the study. Personality traits were measured online one week prior to a laboratory session in which two psychosocial stress tests were administered. Prior to the second test, the placebo group received an intranasal spray of ‘serotonin’ (placebo) with the suggestion that it would enhance recovery. Subjective stress, heart rate and heart rate variability were measured. Self reported and physiological responses to the placebo suggestion were assessed against personality variables.

Results

Placebo effects were demonstrated in both self reported and physiological stress metrics. Lower optimism and less empathic concern predicted greater perceived benefits from the placebo treatment; and lower drive, fun, and sensation seeking were related to a greater physiological response to the manipulation. Multivariate analyses revealed lower optimism and behavioural drive to be predictive of responding to the placebo manipulation.

Conclusion

Findings are in contrast with prior work in pain paradigms which found higher levels of the same traits to be related to greater placebo analgesic responses. A cluster of traits characterised by behavioural drive, extraversion, optimism and novelty or fun seeking appears to be germane to placebo responsiveness, but contextual stimuli may generate different patterns of responding. A new conceptualisation of placebo responsiveness may be useful. Rather than a ‘placebo personality’ it may be that responsiveness is better typified by a two faceted transactional model, in which different personality facets respond to different contextual contingencies.     

The effects of strength,aerobic, and concurrent exercise on skeletal muscle damage in rats

Introduction: In this study we examined oxidative stress and skeletal muscle damage resulting from acute strength, aerobic, or concurrent exercise in rats. Methods: The animals were divided into control (C), strength (SE), aerobic (AE), and combined (CE) exercise groups. They were euthanized at 3 different time‐points (6, 24, and 48 h) after acute exercise. Results: SE exercise rats had increased dichlorofluorescein oxidation at 6 h post‐exercise and decreased superoxide dismutase activity at all time‐points. Glutathione peroxidase activity and sulfhydryl levels were increased in the AE group at 48 h post‐exercise. Serum lactate dehydrogenase activity was increased in the SE and CE groups at 24 h and in the AE group at 48 h. Echo intensity was elevated at 24 h for all groups. Conclusions: Forty‐eight hours was sufficient for complete recovery from oxidative stress and muscle damage in the SE and CE groups, but not in the AE group. Muscle Nerve 50 : 79–86, 2014     

Motor function and respiratory capacity in patients with late‐onset pompe disease

Introduction: The relationship between skeletal muscle strength and respiratory dysfunction in Pompe disease has not been examined by quantitative methods. We investigated correlations among lower extremity proximal muscle strength, respiratory function, and motor performance. Methods: Concentric strength of the knee extensor and flexor muscles was measured with a dynamometer, and pulmonary function was evaluated using spirometry in 7 adult patients. The 6‐minute walk test and the 4‐step stair‐climb test were used for assessing aerobic endurance and anaerobic power, respectively. Results: Anaerobic motor performance correlated with strength of both thigh muscles. Respiratory function did not correlate with either muscle strength or motor function performance. Conclusions: Respiratory and lower extremity proximal muscles could be affected differentially by the disease in individual patients. Motor performance is influenced by thigh muscle strength and is less dependent of respiratory capacity in our cohort of ambulatory patients. Muscle Nerve 49:603–606, 2014     

实时三维超声心动图对两类不同病因心力衰竭患者左心室收缩同步性的临床研究

目的 比较缺血性心脏病与扩张型心肌病两类病因引起的慢性心力衰竭(心衰)患者左室收缩同步性.并分析两组患者不同步性指数(SDI)与左室射血分数(LVEF)的相关性.方法 43例心衰患者分为两组,A组为17例缺血性心脏病引起的心衰患者;B组为26例扩张型心肌病引起的心衰患者.应用实时三维超声心动图(RT一3DE)的全容积显像模式采集左室三维数据库,并用Qlab定量分析软件对其进行分析,获得左室舒张末容积(EDV)、收缩末容积(ESV)和左室射血分数(LVEF)、17节段"牛眼"图,16节段(除外心尖帽)收缩达最小容积时间的标准差并以心率校正后(Tmsv 16-SD/R-R)的百分数作为左室SDI.结果 A、B两组人选患者的年龄、心率、LVEF和EDV差异均无统计学意义(P>0.05);A组的SDI略低于B组,但差异无统计学意义,17节段"牛眼"图显示两组患者左室收缩延迟节段的位置分布各有不同;对数回归分析显示A、B两组的SDI与LVEF均呈良好的负相关(r=-0.83,r=-0.71,P< 0.01).结论 缺血性心脏病与扩张型心肌病心衰患者左室均存在一定程度的收缩不同步,SDI与左室整体收缩功能存在负相关,随收缩功能的减低而增加,两组收缩延迟节段的位置分布各有不同.     

Similarity preserving low-rank representation for enhanced data representation and effective subspace learning

Latent Low-Rank Representation (LatLRR) delivers robust and promising results for subspace recovery and feature extraction through mining the so-called hidden effects, but the locality of both similar principal and salient features cannot be preserved in the optimizations. To solve this issue for achieving enhanced performance, a boosted version of LatLRR, referred to as Regularized Low-Rank Representation (rLRR), is proposed through explicitly including an appropriate Laplacian regularization that can maximally preserve the similarity among local features. Resembling LatLRR, rLRR decomposes given data matrix from two directions by seeking a pair of low-rank matrices. But the similarities of principal and salient features can be effectively preserved by rLRR. As a result, the correlated features are well grouped and the robustness of representations is also enhanced. Based on the outputted bi-directional low-rank codes by rLRR, an unsupervised subspace learning framework termed Low-rank Similarity Preserving Projections (LSPP) is also derived for feature learning. The supervised extension of LSPP is also discussed for discriminant subspace learning. The validity of rLRR is examined by robust representation and decomposition of real images. Results demonstrated the superiority of our rLRR and LSPP in comparison to other related state-of-the-art algorithms.     

多普勒超声测定左心室Max（dp／dt）的新方法

心室内压力变化率峰值Ｍａｘ（ｄｐ／ｄｔ）是一项评价心肌收缩功能的重要指标。但其测定常需借助于心导管术，临床应用受到限制。依据流体力学基本定律，本文提出：等容收缩期内表现为压力的势能将在射血期部分地转化为以１／２ｐＶ２为形式的动能，因而势能的最大变化率Ｍａｘ（ｄｐ／ｄｔ）将在动能的最大变化率Ｍａｘ（ｄｋ／ｄｔ）上得到反映。应用特制计算机软件将主动脉血流速度曲线转化为４Ｖ２曲线，该曲线的一级导数峰值即为Ｍａｘ（ｄｋ／ｄｔ）。应用脉冲多普勒超声测定２３例先天性心脏病患儿的主动脉血流频谱参数并与心导管测定的左心室Ｍａｘ（ｄｐ／ｄｔ）进行对比分析。结果显示：主动脉血流频谱参数Ｍａｘ（ｄｋ／ｄｔ）与左心室Ｍａｘ（ｄｐ／ｄｔ）呈良好相关（ｒ＝０．８１７，Ｐ＜０．００１），直线回归方程为：Ｍａｘ（ｄｐ／ｄｔ）＝０．４７Ｍａｘ（ｄｋ／ｄｔ）＋６７．９（Ｋｐａ／ｓ），平均加速度ｍＡ及Ｖｐ２／ＡＴ与Ｍａｘ（ｄｐ／ｄｔ）亦有较好的相关性。表明由多普勒超声获得的主动脉血流频谱参数Ｍａｘ（ｄｋ／ｄｔ）能较准确地估侧左室Ｍａｘ（ｄｐ／ｄｔ），因而可作为评价心脏收缩功能的可靠指标     

电影MR对测定心功能价值的探讨

目的探讨电影MR测定心功能的价值。材料和方法；通过对21例健康成人电影MR成像，采用双盲法，分析和测量左心功能指标，并与超声心动图（UCG）测值进行相关性t检验。结果：电影MR测定左室短径、左室后壁／室间隔厚度、左室舒末／缩末容积等指标，与UCG比较，具有良好的相关性（r＝0．87－0．99）。结论：电影MR是又一检测心功能准确、无创的影像新技术，具有较大发展潜力。