多粘菌素B对小白鼠右心室肌动作电位的影响

The effects of polymyxin B (PXB) on action potential of the mice right ventricular myocardial cell were studied by means of intracellular capillary glass electrode. The action potential amplitude (APA) and maximal depolarization rate of phase O (V_max) of action potential were lowered after administering PXB for 5 min. APA was lowered from 104.0±4.2 mV to 100.7±5.1mV, decreasing 3.2% (P<0.01); V_max was lowered from 691.5±114.1 v/s to 515.15±71.5 v/s, decreasing 25.5% (P<0.001). Practically, the resting potential remained unchanged. With the continued administration of PXB, the functional refractory period was significantly prolonged. APA₉₀ was temporarily shortened and then prolonged. The results suggest that PXB inactivate or block the fast sodium channel in myocardial cell membrane, which may relate to the antiarrhythmic effect in animal experiment.     

肥胖儿童静息能量消耗的初步研究

目的　应用能量代谢仪测定肥胖儿童的静息能量消耗情况,以探讨安静状态下代谢水平与儿童肥胖的关系,同时比较各预测公式的准确性。方法　选取2014年7月至2015年9月在本院儿童保健科就诊的年龄在7～14周岁的儿童。应用间接测热法测静息能量消耗,应用生物电阻抗法测体脂、去脂体质量等体成分。以预测公式值与实测值误差在±10%之内为可以接受的“准确”,超过10%为“高估”,低于10%为“低估”。结果　共纳入研究对象72例,其中超重/肥胖组42例,平均年龄(10.4±1.7)岁,体质量指数(24.76±3.16)kg/m2;对照组共30例,平均年龄(10.4±2.0)岁,体质量指数(15.07±2.11)kg/m2。静息能量消耗以kJ/(kg·d)表示,校正性别、年龄的影响因素后肥胖组儿童每天静息能量消耗［(116.45±20.46)kJ/(kg·d)］明显低于对照组［(138.49±38.77) kJ/(kg·d)］(P=0.000)。各预测公式准确性尚无一致性定论,研究对象实测值与Harris-Benedict、Schofield、WHO、Mifflin、Cunningham、Liu、Jia公式完全符合的准确率分别为50%、47.6%、42.9%、47.6%、33.3%、42.9%、40.5%。结论　肥胖儿童静息能量消耗低于正常儿童,与间接测热法比较,各预测公式准确性均较差。     

海洛因成瘾者后扣带回结构和功能连接的磁共振研究

目的 应用基于体素的形态测量学和静息态功能磁共振研究海洛因成瘾者后扣带同结构和功能连接的变化情况.方法 14例海洛因成瘾者和13例正常对照者分别采集3DT1WI图像和静息态功能磁共振图像,对3DT1WI图像进行基于体素的形态测量学分析以了解相关脑区灰质密度和体积的变化,对功能磁共振图像分别以左、右后扣带同为感兴趣区与全脑的体素进行相关分析,比较海洛因成瘾组与正常对照组的后扣带回结构和功能连接的变化情况.结果 与正常对照相比,海洛因成瘾组的后扣带回灰质密度显著降低;以左侧后扣带回为感兴趣区进行功能连接分析,海洛因成瘾组左侧后扣带回与右侧颞叶的功能连接高于正常对照组,与右侧前额叶、丘腩以及左侧顶叶的功能连接明显低于正常对照组;以右侧后扣带回为感兴趣区进行功能连接分析,海洛因成瘾组右侧后扣带回与左侧额叶、左侧顶叶以及丘脑的功能连接明显低于正常对照组(双样本t检验,P<0.01).结论 海洛因成瘾者后扣带回的结构和功能连接异常,这与海洛因成瘾的脑结构和功能障碍以及奖赏系统障碍有关.

Abstract：

Objective To explore the abnormalities in the posterior cingulated cortex structure by voxel based morphometry(VBM)and changes of functional connectivity by resting-state functional magnetic resonance imaging(fMRI)in long-term heroin addictions.Methods High-resolution volumetric T1-weighted images and resting state fMRI examination were performed on 13 long-term heroin addicts and 14 matched healthy volunteers.The T1-weighted images were processed using optimized voxel-based morphometry to investigate abnormalities in the gray matter,at the sarne time,the posterior cingulated cortex was setted as the region-of-interest(ROI)seed,with which a whole-brain voxel temporal correlation in low frequency fMRI fluctuations was calculated,to find changes of the posterior cingulated cortex functional connectivity.Results Compared with the control group,gray matter concentration significantly decreased in the posterior cingnlated cortex,at the same time,the functional connectivity between the left posterior cingulated cortex and the right temporal lobe was increased,but the functional connectivity between the left posterior eingulated cortex and the left thalamus,the left parietal lobe,the left cerebrum were all decreased in heroin addicts.At the same time,the functional connectivity between the fight posterior cingulated cortex and the left thalamus,the left parietal lobe,the left frontal lobe were decreased in heroin addicts(t testing,P<0.01).Conclusion The structure and the functional connectivity in posterior cingulated cortex in long-term heroin addicts are changed,which may affect the dysfunction of the addictive brain and the function of reward mechanism.     

老年高血压患者静息心率增加对靶器官损害的临床研究

目的探讨老年原发性高血压(EH)患者静息心率(RHR)与靶器官损害的关系。方法入选老年EH患者206例,按RHR水平分为RHR1组<70次/min(56例),RHR2组70次≤RHR<80次/min(84例),RHR3组RHR≥80次(66例)三组。对人选患者做以下检查心电图、超声心动图、颈动脉超声、肌酐清除率以及尿微量白蛋白。结果(1)RHR2组和RHR3组的颈动脉内膜厚度(IMT)、颈动脉内径(CAD)、左心室重量指数(LVMI)以及尿微量白蛋白定量(MAU)均高于RHR1组(P<0.01),而左室射血分数(LVEF)、肌酐清除率小于RHR1组(P<0.01)。(2)RHR与IMT、CAD、LVMI、MAU呈正相关(r分别为0.312、0.289、0.630、0.576,P<0.01),而与LVEF、肌酐清除率呈负相关(r分别为-0.563、-0.510,P<0.01)。(3)非条件Logistic回归分析显示,RHR、收缩压(SBP)、舒张压(DBP)、脉压(PP)对高血压性心脏病、冠心病、心力衰竭、脑血管意外和肾功能损害有不同程度的影响(P<0.05或P<0.01),其中SBP和RHR的作用更大。结论RHR可能是老年EH患者靶器官损害的独立危险因素。     

Granger因果分析1型糖尿病患儿静息态fMRI数据

目的 观察1型糖尿病（T1DM）患儿静息态fMRI双侧海马效应连接的变化。方法 对1型T1DM患儿（n=18,T1DM组）和健康儿童（n=13,对照组）行静息态fMRI数据采集,以双侧海马为ROI进行Granger因果分析。结果 与对照组比较,以左侧海马为种子点,T1DM组左侧海马对双侧额中回、岛盖部额下回、三角部额下回、中央后回、辅助运动区、脑岛、前扣带和旁扣带脑回、内侧扣带和旁扣带脑回、缘上回,左侧内侧额上回、中央前回,右侧背外侧额上回的外向流显著减弱;以右侧海马为种子点,T1DM组右侧海马对双侧辅助运动区、内侧扣带和旁扣带脑回,左侧的额中回、岛盖部额下回、三角部额下回、内侧额上回、中央后回、前扣带和旁扣带脑回、缘上回外向流显著减弱。结论 T1DM患儿海马功能可能受到损伤,导致额叶、辅助运动皮层、扣带皮层对海马信息的提取能力减弱;与右侧海马相比,左侧海马可能对认知处理的参与度更高;海马外向流减弱对T1DM相关认知损害具有早期警示作用。     

Functional brain connectivity and cognition: effects of adult age and task demands

Previous neuroimaging research has documented that patterns of intrinsic (resting state) functional connectivity (FC) among brain regions covary with individual measures of cognitive performance. Here, we examined the relation between intrinsic FC and a reaction time (RT) measure of performance, as a function of age group and task demands. We obtained filtered, event-related functional magnetic resonance imaging data, and RT measures of visual search performance, from 21 younger adults (19–29 years old) and 21 healthy, older adults (60–87 years old). Age-related decline occurred in the connectivity strength in multiple brain regions, consistent with previous findings. Among 8 pairs of regions, across somatomotor, orbitofrontal, and subcortical networks, increasing FC was associated with faster responding (lower RT). Relative to younger adults, older adults exhibited a lower strength of this RT-connectivity relation and greater disruption of this relation by a salient but irrelevant display item (color singleton distractor). Age-related differences in the covariation of intrinsic FC and cognitive performance vary as a function of task demands.     

Default network is not hypoactive in dementia with fluctuating cognition: an Alzheimer disease/dementia with Lewy bodies comparison

Default mode network resting state activity in posterior cingulate cortex is abnormally reduced in Alzheimer disease (AD) patients. Fluctuating cognition and electroencephalogram abnormalities are established core and supportive elements respectively for the diagnosis of dementia with Lewy bodies (DLB). Our aim was to assess whether patients with DLB with both of these features have different default mode network patterns during resting state functional magnetic resonance imaging compared with AD. Eighteen patients with DLB, 18 AD patients without fluctuating cognition, and 15 control subjects were selected after appropriate matching and followed for 2–5 years to confirm diagnosis. Independent component analysis with functional connectivity (FC) and Granger causality approaches were applied to isolate and characterize resting state networks. FC was reduced in AD and DLB patients compared with control subjects. Posterior cingulate cortex activity was lower in AD than in control subjects and DLB patients (p < 0.05). Right hemisphere FC was reduced in DLB patients in comparison with control subjects but not in patients with AD, and was correlated with severity of fluctuations (ρ = −0.69; p < 0.01). Causal flow analysis showed differences between patients with DLB and AD and control subjects.     

Positive association between serum quinolinic acid and functional connectivity following concussion

The molecular mechanisms underlying the diverse psychiatric and neuropathological sequalae documented in subsets of athletes with concussion have not been identified. We have previously reported elevated quinolinic acid (QuinA), a neurotoxic kynurenine pathway metabolite, acutely following concussion in football players with prior concussion. Similarly, work from our group and others has shown that increased functional connectivity strength, assessed using resting state fMRI, occurs following concussion and is associated with worse concussion-related symptoms and outcome. Moreover, other work has shown that repetitive concussion may have cumulative effects on functional connectivity and is a risk factor for adverse outcomes. Understanding the molecular mechanisms underlying these cumulative effects may ultimately be important for therapeutic interventions or the development of prognostic biomarkers. Thus, in this work, we tested the hypothesis that the relationship between QuinA in serum and functional connectivity following concussion would depend on the presence of a prior concussion. Concussed football players with prior concussion (N = 21) and without prior concussion (N = 16) completed a MRI session and provided a blood sample at approximately 1 days, 8 days, 15 days, and 45 days post-injury. Matched, uninjured football players with (N = 18) and without prior concussion (N = 24) completed similar visits. The association between QuinA and global connectivity strength differed based on group (F(3, 127) = 3.46, p = 0.019); post-hoc analyses showed a positive association between QuinA and connectivity strength in concussed athletes with prior concussion (B = 16.05, SE = 5.06, p = 0.002, 95%CI[6.06, 26.03]), but no relationship in concussed athletes without prior concussion or controls. Region-specific analyses showed that this association was strongest in bilateral orbitofrontal cortices, insulae, and basal ganglia. Finally, exploratory analyses found elevated global connectivity strength in concussed athletes with prior concussion who reported depressive symptoms at the 1-day visit compared to those who did not report depressive symptoms (t(15) = 2.37, mean difference = 13.50, SE = 5.69, p = 0.032, 95%CI[1.36, 25.63], Cohen’s d = 1.15.). The results highlight a potential role of kynurenine pathway (KP) metabolites in altered functional connectivity following concussion and raise the possibility that repeated concussion has a “priming” effect on KP metabolism.     

中老年女性静息心率与代谢综合征及其组分间的关联性研究

目的：探讨中老年女性静息心率(RHR)与代谢综合征(MetS)及其相关组分之间的关联性。方法以2010年1月至2014年6月在珠海市人民医院体检科参与体检的862例中老年女性为研究对象,测量其静息心率(RHR)、身高、体重、腰围(WC)、血压、空腹血糖(FPG)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL)、低密度脂蛋白胆固醇(LDL),并将研究对象按照RHR四分位数法分4组：≤70次/min、71~75次/min、76~80次/min、≥81次/min。比较不同RHR组中老年女性MetS及其各组分的患病差异;以≤70次/min组作为对照,采用Logistic回归模型分析其余3组MetS的患病风险。结果 MetS患病率随着RHR的增加呈上升趋势(χ2trend=5.23,Pt rend=0.02),≥81次/min组MetS患病率为48.5%,显著高于≤70次/min (32.4%)、71~75次/min组(37.3%)和76~80次/min组(37.9%),差异均有统计学意义(P<0.05);MetS组分析结果显示：收缩压(Ftrend=12.38,Ptrend=0.002)、FPG (Ftrend=8.56, Pt rend=0.004)和TG (Ftrend=8.53,Ptrend=0.004)随RHR加快而升高,HDL随RHR加快而降低(Ftrend=18.56,Pt rend<0.01),差异均有统计学意义(P<0.05)。多因素Logistic回归分析显示,≥81次/min组中老年女性患MetS的风险较≤70次/min组增加了57%(OR=1.57,95%CI=1.08~2.29)。结论 RHR与MetS及其组分间存在相关性,可作为MetS发病的一个预测指标,为诊断和防控MetS患者进展为心脑血管疾病等不良结局提供了新的靶点和研究方向。