Rat occipital cortical synapses after ovariectomy

Our laboratory reported an increase in the thickness of the occipital cortex in 90-day-old female Long-Evans rats ovariectomized on day 1 compared with sham-operated controls. The present experiment studied the effects of ovariectomy on cerebral cortical synapses. Tissue blocks from the dorsal medial occipital cortex, area 18, of the right hemisphere were examined with a Zeiss 9S-2 electron microscope, magnification 34,125. Significantly more discontinuous postsynaptic densities were observed in the ovariectomized animals than in the sham-operated rats. The ovariectomized group also showed more positively curved synapses and fewer negatively curved synapses than the sham-operated animals, according to the scheme of synaptic curvature outlined by R. M. Devon and D. G. Jones (1979, Cell Tissue Res.203, 189–200) and S. E. Dyson and D. G. Jones (1980, Brain Res.183, 43–59). These data may represent the presence of more mature, active, functioning synapses in animals that have been ovariectomized compared with their littermate controls.     

Hepatocyte growth factor improves synaptic localization of the NMDA receptor and intracellular signaling after excitotoxic injury in cultured hippocampal neurons

To examine the effects of HGF on synaptic densities under excitotoxic conditions, we investigated changes in the number of puncta detected by double immunostaining with NMDA receptor subunits and presynaptic markers in cultured hippocampal neurons. Exposure of hippocampal neurons to excitotoxic NMDA (100 muM) decreased the synaptic localization of NMDA receptor subunit NR2B, whereas synaptic NR1 and NR2A clusters were not altered. Colocalization of PSD-95, a scaffolding protein of the receptor, with the presynaptic protein synapsin I was also decreased after excitotoxicity. Treatment with HGF attenuated these decreases in number. The decrease in the levels of surface NR2B subunits following the addition of the excitotoxic NMDA was also attenuated by the HGF treatment. The decrease in CREB phosphorylation in response to depolarization-evoked NMDA receptor activation was prevented by the HGF treatment. These results suggest that HGF not only prevented neuronal cell death but also attenuated the decrease in synaptic localization of NMDA receptor subunits and prevented intracellular signaling through the NMDA receptor.     

Course and predictors of medically unexplained pain symptoms in the general population

OBJECTIVE: The objective of this study was to explore the course and the predictors of clinically significant medically unexplained pain symptoms (MUS-pain) within the 6 months preceding the interviews at baseline and on follow-up in the general population. METHODS: A Norwegian general population study of 605 persons interviewed with the Composite International Diagnostic Interview Somatoform Section was conducted in 1989/1990 (baseline), and 421 persons (69.6% response rate; 242 women and 179 men) were reinterviewed in 2000/2001 (follow-up). Cases of recent MUS-pain compared with those at baseline were assessed on follow-up. Four blockwise logistic regression analyses were undertaken to find predictors (such as stressful life events, living alone, depression and anxiety, and physical morbidity) for recent MUS-pain in 2001. RESULTS: A small "stable" group of recent MUS-pain sufferers (8% of all reinterviewed and 33.6% of those with recent MUS-pain at baseline) was evident. In this group almost all were women. In addition to female gender being a significant (P<.05) marker of recent MUS-pain (which gives a twofold-higher risk compared with men), only depression--not the occurrence of prior recent MUS-pain--remained a significant (P<.05) predictor in the final model, increasing the likelihood of having recent MUS-pain by threefold. CONCLUSION: The prognosis of MUS-pain is relatively good, except for a small group (mainly women) that is prone to chronicity. Clinicians should examine for depression when confronted with MUS-pain patients and should be aware of the twofold-higher risk in women for persistent MUS-pain over a long time.     

Developmental changes in the association of NMDA receptors with lipid rafts

Lipid rafts (LR) are lipid microdomains present in the cell surface membrane that are organizational platforms involved in protein trafficking and formation of cell signaling complexes. In the adult brain, NMDA receptors (NMDAR) and receptor-associated proteins such as membrane-associated guanylate kinases (PSD-95 and SAP102), are distributed between the postsynaptic density (PSD) and lipid rafts. However, the time course of the association of NMDAR with LR during neural development is not known. We therefore investigated the effect of development on the association of NMDAR with LR prepared from rat brains ranging in postnatal age from 1-35 days and compared this with their expression in PSDs. LR and PSD fractions were prepared by extraction of P2 membranes with Tx-100 followed by sucrose density gradient centrifugation. The yield of LR, as reflected by levels of protein, Thy-1, and flotillin-1 increased during postnatal development. NR2A was associated predominantly with the lipid raft fraction at all ages examined whereas NR2B underwent a gradual shift from PSDs to lipid rafts during the first 3 weeks after birth. These changes in the distribution of NR2A and NR2B were paralleled by changes in the distribution of PSD-95 and SAP102 respectively. Tyrosine-phosphorylated proteins, including NR2A and NR2B, were preferentially associated with lipid rafts in older, as compared to younger, animals. These results show that the association of NMDAR with LR is regulated developmentally.     

The GLUR2 subunit of AMPA receptors: synaptic role

Ampa receptors mediate the majority of excitatory synaptic transmission in the brain. Thus, the mechanisms that control the developmental and activity-dependent changes in the functional synaptic expression of AMPA receptors are of fundamental importance. Here we focus on the role of GluR2 subunit in synaptic function and plasticity.     

视皮层LTP诱导过程中的突触形态计量学研究

使用生后18～20天龄的幼年大鼠视皮层脑片标本，在LTP出现后半小时进行超微结构观察。运用白象分析仪分别对以下参数进行测量：（1）突触间隙的宽度；（2）突触后致密物（PSD）的厚度；（3）活性区的长度；（4）突触界面曲率。用双官法对突触数目进行计量，并用立体计量学方法对各种突触类型进行定量，结果显示：（1）LTP形成后半小时之内，突触反应增强，最大可达基础反应的516％；（2）PSD的厚度明显增厚；（3）活性区的面密度及突触界面曲率在备组间无明显差异；（4）穿孔性突触的数密度与对照组相比无显著差异；（5）总突触数目和棘突触数目的数密度较对照组明显增高。结果提示，PSD的增厚可能是LTI，诱导过程的形态学特征。在LTP的诱导过程中，突触数目有明显增加的趋势。     

早期心理干预对脑卒中后抑郁患者运动功能康复的影响

目的：评价早期心理干预对脑卒中后抑郁（PSD）患者运动功能康复的影响。方法：70例急性PSD患者随机分成两组各35例，对照组给予Bobath方法训练，干预组除上组方法外加心理干预。结果：干预组运动功能康复临床效果评分明显优于对照组。结论：PSD的早期心理干预较一般康复方法促进脑卒中患者运动功能的恢复。     

Cardiac autonomic activity in methylmercury neurotoxicity: 14-year follow-up of a Faroese birth cohort

OBJECTIVE: To determine whether heart function in childhood is affected by exposure to methylmercury (MeHg) from seafood. STUDY DESIGN: Prospective study of a Faroese birth cohort (N=1022). Examinations at ages 7 and 14 years included blood pressure, heart rate variability (HRV) and its frequency components of autonomic origin, and brainstem auditory evoked potentials (BAEPs). Mercury concentrations were determined in cord blood and in the child's hair. RESULTS: Both low-frequency (LF) and high-frequency (HF) activities decreased by about 25% from 7 to 14 years; they correlated well with the blood pressures. A doubling of prenatal MeHg exposure was associated with a decrease in LF and HF powers of about 6.7% (P=.04) and in the coefficient of variation of the electrocardiographic R-R interval of 2.7% (P=.04) at age 14 years. No discernible effect on blood pressure was apparent. Decreased LF variability was associated with increased latency of BAEP peak III, but adjustment for MeHg exposure substantially attenuated this correlation. CONCLUSIONS: Methylmercury exposure was associated with decreased sympathetic (LF) and parasympathetic (HF) modulation of the HRV. Parallel MeHg-related delays of BAEP latencies may be caused by underlying MeHg neurotoxicity to brainstem nuclei.     

丁苯酞治疗卒中后抑郁40例效果观察

目的观察丁苯酞对卒中后抑郁（PSD）的疗效。方法将我院2011年11月至2012年4月确诊的PSD患者随机分为治疗组40例和对照组40例,分别于治疗第1个月时进行汉密尔顿抑郁量表（HAMD）评分,并计算两组的有效率。结果治疗组治疗1个月后与治疗前相比HAMD评分减低．分别为11．75±2．89与20．52±2．47,抑郁程度改善显著,差异有统计学意义（P〈0．05）;治疗组与对照组在治疗1月后HAMD评分分别为11．75±2．89与15．25±3．73,差异有统计学意义（P〈o．05）;治疗组与对照组的有效率分别为77．5％（31／40）与55．o％（22／40）,差异有统计学意义（P〈0．05）。结论丁苯酞在一定程度上可改善PSD患者的临床症状．对PSD有一定疗效。     

Noise reduction based on ICA decomposition and wavelet transform for the extraction of motor unit action potentials

We have studied methods for noise reduction of myoelectric signals and for extraction of motor unit action potentials from these signals. Effective MUAP peak detection is the first important step in EMG decomposition. We first combined independent component analysis and wavelet filtering to remove power line interference, and then applied a wavelet filtering method and threshold estimation calculated using wavelet transform to suppress background noise and Gaussian white noise. The technique was applied to single-channel, short-period real myoelectric signals from normal subjects and to artificially generated EMG recordings. In contrast to existing methods based on amplitude single-threshold filtering of the original myoelectric signal or a conventional digitally filtered signal, our technique is fast and robust. Moreover, the proposed algorithm is substantially automatic. The performance has been evaluated with a set of synthetic and experimentally recorded myoelectric signals. The basic tool for testing was power spectrum density (PSD) estimation by the Welch method, which allowed us to analyze the PSD of nonstationary signals.