Changes in lower limb co-contraction and stiffness by toddlers with Down syndrome and toddlers with typical development during the acquisition of independent gait

During gait acquisition, children learn to use their changing resources to meet the requirements of the task. Compared to typically developing toddlers (TD), toddlers with Down syndrome (DS) have functionally different musculoskeletal characteristics, such as hypotonia, and joint and ligament laxity, that could produce a reduced passive stiffness. The interplay between this inherently lower passive stiffness and the demands of walking may result in different strategies during gait acquisition. This study compared normalized global stiffness and lower limb's co-contraction indices (CCI) used by toddlers with TD (n=12) and with DS (n=12), during the early stages of gait acquisition. Stiffness and CCI were normalized by gravitational torque (mLg) in both phases of gait (stance, swing). Five longitudinal evaluations were conducted from the onset of locomotion until three months post-acquisition. All children were video taped and had electromyographic (EMG) recordings from muscle pairs of one leg, which were used to calculate CCI of hip, knee, ankle, and total leg CCI. Body and lower limb stiffness were calculated according to a hybrid pendulum resonance equation. Results from ANOVAs revealed no group differences on stiffness or on CCI's during stance but children with DS showed greater CCI during swing. Despite the structural musculoskeletal differences between toddlers with TD and with DS, the similarities observed in their processes of gait development suggest functional equivalences.     

Memory abilities in Williams syndrome: Dissociation or developmental delay hypothesis?

Williams syndrome (WS) is a neurodevelopmental genetic disorder often described as being characterized by a dissociative cognitive architecture, in which profound impairments of visuo-spatial cognition contrast with relative preservation of linguistic, face recognition and auditory short-memory abilities. This asymmetric and dissociative cognition has been also proposed to characterize WS memory ability, with sparing of auditory short-term memory and impairment of spatial and long-term memory abilities. In this study, we explored the possibility of a double memory dissociation in WS (short- versus long-term memory; verbal versus visual memory). Thus, verbal memory abilities were assessed using California Verbal Learning Test and Digit Span and Rey-Osterrieth Complex Figure and Corsi Blocks was used to assess visual-spatial memory abilities. Overall, WS subjects were found to present a generalized significant impairment in verbal and visuo-spatial components either in short- or long-term memory. In sum, data from this study brings support for a developmental delay hypothesis, rather than a double dissociation within memory systems in WS.     

Fragile X syndrome: Neural network models of sequencing and memory

A comparative framework of memory processes in males with fragile X syndrome (FXS) and typically developing (TYP) mental age-match children is presented. Results indicate a divergence in sequencing skills, such that males with FXS recall sequences similarly to TYP children around five and a half years of age, but the males with FXS recall significantly worse when compared to TYP children around seven and a half years of age. Performance on one working memory measure, an n-back Card Task, is modeled with a neural network. To date, no network models explicate the sequencing and memory processes in those with FXS. Noise was added to various levels (weight matrices) in the FXS model and outputs approximated human FXS performance. Three models were compared: (1) FXS; (2) younger mental age-TYP matches; (3) older reading level-TYP matches. Modeling can help to reify conceptualizations of deficits and to guide in the creation of more valid, science-based remediations. The FXS model suggested that the levels of phonological representation and sequencing in memory were candidates for targeted therapies in males with FXS.     

代谢综合征在临床应用中的去留

代谢综合征的概念由来已久,迄今已有数千个围绕代谢综合征的相关研究,探讨其病理生理机制、诊断标准、流行病学、与心血管疾病的相关性及治疗等。然而近年来,代谢综合征的临床适用性及对心血管病和糖尿病的防治意义被质疑,引发了诸多争议。对于“代谢综合征之去留”问题,目前仍不是盖棺定论之时。     

代谢综合征发病机制研究进展

随着经济的发展和人们生活水平的提高以及生活方式的改变,代谢综合征（metabolic syndrome,MS）的患病率逐年上升。代谢综合征是一种涉及多种代谢异常、与心血管病紧密联系的疾病状态。肥胖或超重、糖调节异常或糖尿病、高血压和高血脂是MS的重要组成元素。代谢综合征一直是人们关注的热点,但截止目前确切机制仍不明确。主要围绕肥胖与胰岛素抵抗展开研究,特别是在脂毒性和脂肪分泌因子的调控以及各种炎性因子的影响方面取得了一些进展。     

Different Associations of Health Related Quality of Life with Pain,Psychological Distress and Coping Strategies in Patients with Irritable Bowel Syndrome and Inflammatory Bowel Disorder

The primary aim of this study was to measure psychological distress, pain severity, health related quality of life (QOL) and pain coping strategies in patients with irritable bowel syndrome (IBS) and ulcerative colitis (UC). A second aim was to determine the influence of somatic and psychological variables on health related QOL. Eighty-eight IBS and 66 UC patients completed the Irritable Bowel Syndrome Quality of Life Questionnaire (IBSQOL), Pain Severity Scale of West Haven Yale Multidimensional Pain Inventory (WHYMPY), Symptom Checklist-90-R (SCL-90-R) and Coping Strategies Questionnaire (CSQ). T-tests and GLM Analysis of Covariance were used for statistical analysis. IBS patients had significantly higher levels of psychological distress, pain severity and maladaptive pain coping strategies (catastrophization), and lower QOL than UC patients. Variance of QOL in IBS was explained for the most part by catastrophization (15%), then by psychological distress (8%), and for the less part by pain severity (5%). In UC, pain severity explained 21%, psychological distress 8%, and catastrophization 3% of the variance of QOL. These results suggest there are differences between IBS and UC patients in the role of physical and psychological factors in QOL and emphasize the importance of cognitive processes in IBS.     

系统生物学引导阿尔茨海默病治疗新策略

阿尔茨海默病(AD)是一种发生于中老年期的退行性脑神经变性疾病,临床上以进行性智能衰退,伴有人格改变为主要特征.其发病过程涉及许多途径和靶点.现代医学认为脑内胆碱能递质功能紊乱、β-淀粉样蛋白沉积、tau-蛋白过磷酸化、炎症反应以及基因突变等在其发病过程中起着重要作用.治疗方法从胆碱酯酶抑制剂、神经递质受体阻滞剂到补气活血、益精填髓、化痰开窍等中医药疗法不等.但抑制剂、阻滞剂等药物阻滞疗法,从单一环节阻断发病途径,忽略了AD发病的整体复杂性.中医辨证论治从整体观念出发,在宏观上治疗AD,对AD的发病缺乏微观深入研究.AD治疗需要借助于“系统生物学”理论的指导.中西医结合为AD的治疗提供了较为科学、有效的途径和发展空间.     

经前期综合征与奖赏进程失调——来自脑电的证据

研究表明, 经前期综合征(Premenstrual syndromes, PMS)女性的情绪平衡性存在问题, 而现有研究多从负性情绪上升的角度考察PMS的发病机制, 而对其正性情绪缺损的关注不足。鉴于正性情绪与奖赏进程密切相关, 本研究试图从奖赏进程失调的角度考察PMS女性与健康女性的差异以及该差异是否存在阶段特异性的问题, 以期从正性情绪缺损的角度揭示其发病机制。具体而言, 分别选取PMS女性与健康女性23名和22名, 考察两组被试在黄体晚期(即经前期)和卵泡早期(即经后期)正性情绪以及完成赌博任务时的脑电数据时域和频域的差异。主观问卷结果显示, PMS女性的愉快和平静情绪低于健康女性, 并且情绪平衡性也低于健康女性, 但无明显的阶段特异性。时域分析结果显示, PMS组在经前期收到奖赏反馈后奖赏正波(reward positivity, RewP)的波幅和差异波(即奖赏条件和惩罚条件下的差值)的波幅均低于健康女性, 进一步的相关分析结果显示, 对于PMS组来说, 经前期奖赏条件下的RewP波幅和差异波波幅与经前期的情绪平衡性显著正相关。频域分析的结果则发现PMS组在经前期奖赏条件下的θ频段(4~7 Hz, 250~400 ms)能量低于健康组。研究表明, PMS女性在经前期的奖赏加工进程存在异常, 表现为对奖赏反馈的预期增强, 而在收到奖赏反馈后又出现了钝化反应, 且奖赏进程的失调与情绪平衡性相关。本研究为理解PMS女性奖赏进程失调的动态加工时程和神经震荡特征及其与情绪平衡性的关系提供了初步的神经生理证据。