Impaired circadian rhythmicity of nociceptive reflex threshold in cluster headache

BACKGROUND: Alteration of circadian rhythmicity involving several endocrinologic and autonomic parameters has been observed in cluster headache. OBJECTIVES: To explore whether circadian failure of the pain control system may exist in cluster headache. METHODS: The nociceptive flexion reflex threshold was studied in 25 patients with episodic cluster headache (14 active, 11 in remission) and 6 patients with chronic cluster headache, along with 10 normal volunteers throughout a 24-hour period. The reflex response was evoked at the level of the biceps femoris by stimulating the sural nerve at the ankle. Single and population mean cosinor methods were used to detect the circadian rhythmicity. RESULTS: In the patients with episodic cluster headache, a significant reduction in the nociceptive flexion reflex threshold was observed in both the active subgroup and the subgroup in remission (P < .05). In these patients, persistence of a significant 24-hour rhythm during both the active period and remission was observed, but a shift of the phase was observed during clinical activity when compared with the remission period. A lack of circadian nociceptive flexion reflex threshold rhythmicity was found in the patients with chronic cluster headache. CONCLUSIONS: Our findings suggest that in cluster headache there may be impairment of the pain control system that is associated with periodic failure of the mechanisms involved in the organization of biological rhythms.     

Human movement-related potentials vs desynchronization of EEG alpha rhythm: a high-resolution EEG study

Movement-related potentials (MRPs) and event-related desynchronization (ERD) of alpha rhythm were investigated with an advanced high-resolution electroencephalographic technology (128 channels, surface Laplacian estimate, realistic head modeling). The working hypothesis was that MRPs and alpha ERD reflect different aspects of sensorimotor cortical processes. Both MRPs and alpha ERD modeled the responses of primary sensorimotor (M1-S1), supplementary motor (SMA), and posterior parietal (PP, area 5) areas during the preparation and execution of unilateral finger movements. Maximum responses were modeled in the contralateral M1-S1 during both preparation and execution of the movement. The SMA and PP responses were modeled mainly from the MRPs and alpha ERD, respectively. The modeled ipsilateral M1-S1 responses were larger and stronger in the alpha ERD than MRPs. These results may suggest that alpha ERD reflects changes in the background oscillatory activity in wide cortical sensorimotor areas, whereas MRPs represent mainly increased, task-specific responses of SMA and contralateral M1-S1.     

Sinus Rhythm Mapping in a Canine Model of Ventricular Tachycardia

The relationship between electrograms recorded during sinus rhythm and the activation sequence during ventricular tachycardia induced by programmed stimulation was investigated in a canine model of myocardial infarction. Thirteen dogs were studied 3 days (n = 10) or 14 days (n = 3) after coronary occlusion. Sixty-three unipolar electrograms were simultaneously recorded with a sock electrode array connected to a digital recording system, and analyzed by computer. Bipolar electrograms were recorded sequentially from the same sites with an analog recorder. Categories of unipolar electrograms were defined with reference to the QRS complex during sinus rhythm as follows: Class A included electrograms with an intrinsic deflection inscribed within the QRS complex, class B included those which did not exhibit any intrinsic rs deflection, and class C included those with an intrinsic deflection inscribed later than QRS. The epicardial distribution of each class of electrograms was significantly different between the preparations with, and those without inducible tachycardia (72% versus 63% of electrograms being in class A, 20% versus 35% in class B, and 8% versus 2% in class C; p less than 0.005). When tachycardia was inducible, class C epicardial electrograms were located in an area extending across the region of infarction, which corresponded to the common reentrant pathway of figure-of-eight patterns mapped during tachycardia. When ventricular tachycardia was not inducible, class B electrograms were recorded all over this region. The morphology of bipolar electrograms had no predictive value in identifying the common reentrant pathway. These results support the view that the inducibility of reentrant tachycardia is dependent upon critically located delayed activity detected during sinus rhythm by unipolar recordings.     

251例老年高血压患者血压昼夜节律异常分析

探讨老年高血压患者血压昼夜节律异常的特点。将老年高血压患者251例按年龄段分为老年1组(60～69岁,n=50)、老年2组(70～79岁,n=88)和老年3组(≥80岁,n=113),分析3组患者动态血压参数、动态血压昼夜节律异常发生率。3组患者动态血压参数,夜间平均收缩压(nSBP) 老年3组高于老年1组(P＜0.01),24 h平均舒张压(24hDBP)老年3组和老年2组均低于老年1组(P＜0.01),白天平均舒张压(dDBP)老年3组和老年2组均低于老年1组(P＜0.01和P＜0.05)。3组的血压昼夜节律异常率分别为78.00%、89.78%和92.04%。血压昼夜节律异常率老年3组显著高于老年1组(P＜0.05)。表明随增龄变化,老年高血压患者昼夜节律异常率增高。老年高血压患者血压昼夜节律异常多数表现为非杓型和反杓型血压,并随增龄变化老年高血压患者昼夜节律异常率增高。     

蓝光与眼健康

蓝光是波长介于400 ～ 500 nm的短波长光,蓝光对视网膜细胞造成损伤的特性引起了学者广泛的关注.同时,它在调节昼夜节律、产生暗视力以及屈光发育等方面具有重要作用.蓝光是否安全？是否该从日常生活中清除？本文对蓝光的作用及安全性问题作一综述.     

A rest-activity biomarker to predict response to SSRIs in major depressive disorder

Most adults with Major Depressive Disorder (MDD) will not experience a remission with the first antidepressant trial. No practical biomarkers presently exist to predict responsiveness to antidepressants. Herein we report pilot data for a rest-activity biomarker of antidepressant response.Fifty-eight medication-free adults with MDD underwent a week-long collection of actigraphic data before beginning a 9 week open label trial of fluoxetine, coupled with blinded randomized assignment to eszopiclone/placebo. Depression severity was repeatedly measured with the Hamilton Rating Scale for Depression (HRSD). Baseline actigraphic data was analyzed with functional data analysis to create smoothed 24-h curves of activity. The time of the lowest point of activity (the bathyphase) was calculated for each patient, as well the mean difference between bedtime and the bathyphase (BBD). At the end of treatment, patients were characterized as treatment responders (50% reduction in HRSD) or non-responders, and receiver operating curves were calculated to find the optimal cut point of the BBD for prediction of treatment response.The best cut point for BBD was at 260.2 min, resulting in an effect size of 1.45, and with a positive predictive value of 0.75 and a negative predictive value of 0.88.We conclude that actigraphically-determined measures of rest-activity patterns show promise as potential biomarker predictors of antidepressant response. However, this conclusion is based upon a small number of patients who received only one choice of antidepressant, for a single trial. Replication with a larger sample is needed.     

电针不同穴位对小鼠自发活动节律的影响

目的:探讨不同穴位电针对小鼠自发性活动节律调整的时相特征。方法:将筛选出的28只C57BL/6J雄性小鼠随机分为百会+长强组,肝俞+至阳组,非经非穴组,空白组4组,每组7只。小鼠先光-暗控制(L∶D为12∶12,即0100-1300光照,1300-0100暗置)14 d,使动物的转轮活动与外界的光-暗周期同步,光暗驯化14 d后关闭光源转为恒定黑暗(Dark-Dark,DD),使小鼠处于自由运行状态(Free-Running,FR)。小鼠暗置条件驯化10天后开始电针。小鼠均在CT16时间点电针,频率2/15Hz,电流0.5 m A,15 min/次,电针1次/d,连续电针7 d,空白组小鼠在相同时间点CT16捆绑固定,不予电针刺激。结果:电针后各组小鼠相位均超前,百会+长强组,肝俞+至阳组峰相位超前具有统计学意义(P0.05),非经非穴组,空白组峰相位移动不具有统计学意义(P0.05);电针后各组活动度均降低,与针刺前比较均具有统计学差异(P0.05)。百会+长强组电针后起始活动时间提前,具有统计学意义(P0.05),其余各组起始活动时间无统计学意义(P0.05)。电针干预后,各组小鼠峰值均降低,但无统计学意义(P0.05)。电针后各组小鼠振幅均降低,但无统计学意义(P0.05)。干预后,各组小鼠周期均延长,但无统计学意义(P0.05)。结论:暗置条件下小鼠自发性活动仍具有明显的昼夜节律性,电针对自由运行状态下小鼠近日节律有一定影响,其时相特征表现为:峰相位、起始活动时间超前,活动度、峰值、振幅降低,周期延长。百会+长强组能显著提前小鼠峰相位、起始活动时间,降低小鼠活动度;电针肝俞+至阳能使小鼠峰相位提前,降低活动度。