Early raise of BDNF in hippocampus suggests induction of posttranscriptional mechanisms by antidepressants

Background  

The neurotrophin BDNF has been implicated in the regulation of neuroplasticity, gene expression, and synaptic function in the adult brain, as well as in the pathophysiology of neuropsychiatric disorders and the mechanism of action of antidepressants. Antidepressant treatments have been shown to increase the expression of BDNF mRNA, although the changes measured were found to be different depending on various factors. A few studies only have measured levels of BDNF protein after antidepressant treatments, and poor correlation was found between mRNA and protein changes. We studied the time course of expression of BDNF mRNA and protein during drug treatments, in order to elucidate the temporal profile of regulation of this effector and whether mRNA and protein levels correlate. Rat groups were treated for 1, 2 or 3 weeks with fluoxetine or reboxetine; in additional groups drug treatment was followed by a washout week (3+1). Total BDNF mRNA was measured by Real Time PCR, pro- and mature BDNF proteins were measured by Western blot.     

Hypoxia-induced transcription of dopamine D3 and D4 receptors in human neuroblastoma and astrocytoma cells

Background

The aim of this study is to examine the influence of the catechol-O-methyltranferase (COMT) gene (polymorphism Val158 Met) as a risk factor for Alzheimer's disease (AD) and mild cognitive impairment of amnesic type (MCI), and its synergistic effect with the apolipoprotein E gene (APOE). A total of 223 MCI patients, 345 AD and 253 healthy controls were analyzed. Clinical criteria and neuropsychological tests were used to establish diagnostic groups. The DNA Bank of the University of the Basque Country (UPV-EHU) (Spain) determined COMT Val158 Met and APOE genotypes using real time polymerase chain reaction (rtPCR) and polymerase chain reaction (PCR), and restriction fragment length polymorphism (RFLPs), respectively. Multinomial logistic regression models were used to determine the risk of AD and MCI.

Results

Neither COMT alleles nor genotypes were independent risk factors for AD or MCI. The high activity genotypes (GG and AG) showed a synergistic effect with APOE ε4 allele, increasing the risk of AD (OR = 5.96, 95%CI 2.74-12.94, p < 0.001 and OR = 6.71, 95%CI 3.36-13.41, p < 0.001 respectivily). In AD patients this effect was greater in women. In MCI patients such as synergistic effect was only found between AG and APOE ε4 allele (OR = 3.21 95%CI 1.56-6.63, p = 0.02) and was greater in men (OR = 5.88 95%CI 1.69-20.42, p < 0.01).

Conclusion

COMT (Val158 Met) polymorphism is not an independent risk factor for AD or MCI, but shows a synergistic effect with APOE ε4 allele that proves greater in women with AD.     

Functional modulation of human delta opioid receptor by neuropeptide FF

Background  

Neuropeptide FF (NPFF) plays a role in physiological pain sensation and opioid analgesia. For example, NPFF potentiates opiate-induced analgesia and the delta opioid receptor antagonist naltrindole inhibits NPFF-induced antinociception. The nature of the interactions between NPFF and opioid receptors seems to be complex and the molecular mechanisms behind the observed physiological effects are not known.     

Frequency modulation controlled by cross-phase modulation in optical fiber

We have generated a frequency-modulated laser beam by use of cross-phase modulation between orthogonally polarized beams in a polarization-preserving optical fiber. This frequency modulation is based on the temporal intensity beating of the drive beam that is caused by another beam that has a slightly different wavelength. Moreover, we have demonstrated generation of a special frequency-modulated laser beam with temporally changing modulation frequency by use of cross-phase modulation in conjugation with self-phase modulation.     

Tissue-specific and neural activity-regulated expression of human BDNF gene in BAC transgenic mice

Background  

Brain-derived neurotrophic factor (BDNF) is a small secreted protein that has important roles in the developing and adult nervous system. Altered expression or changes in the regulation of the BDNF gene have been implicated in a variety of human nervous system disorders. Although regulation of the rodent BDNF gene has been extensively investigated, in vivo studies regarding the human BDNF gene are largely limited to postmortem analysis. Bacterial artificial chromosome (BAC) transgenic mice harboring the human BDNF gene and its regulatory flanking sequences constitute a useful tool for studying human BDNF gene regulation and for identification of therapeutic compounds modulating BDNF expression.     

Discrete nuclear structures in actively growing neuroblastoma cells are revealed by antibodies raised against phosphorylated neurofilament proteins

Background  

Nuclear objects that have in common the property of being recognized by monoclonal antibodies specific for phosphoprotein epitopes and cytoplasmic intermediate filaments (in particular, SMI-31 and RT-97) have been reported in glial and neuronal cells, in situ and in vitro. Since neurofilament and glial filaments are generally considered to be restricted to the cytoplasm, we were interested in exploring the identity of the structures labeled in the nucleus as well as the conditions under which they could be found there.     

Time-dependent scattering of a standing surface plasmon by rapid ionization in a semiconductor

Scattering of a standing surface plasmon by rapid ionization in a semiconductor is investigated. We show that, for a standing plasmon, in contrast with a traveling plasmon, the scattering depends on the plasmon phase at the moment of ionization. By changing the moment of ionization, we can control the energy that is transferred into newly excited modes, which include a frequency-upshifted standing surface plasmon, transient outgoing radiation, and free-streaming currents with a static magnetic field in the semiconductor. The phenomena that are described open new possibilities for probing the dynamics of surface excitations in semiconductors on an ultrashort time scale.     

Time-dependent surface adhesive force and morphology of RBC measured by AFM

Atomic force microscopy (AFM) is a rapidly developing tool recently introduced into the evaluation of the age of bloodstains, potentially providing legal medical experts useful information for forensic investigation. In this study, the time-dependent, morphological changes of red blood cells (RBC) under three different conditions (including controlled, room-temperature condition, uncontrolled, outdoor-environmental condition, and controlled, low-temperature condition) were observed by AFM, as well as the cellular viscoelasticity via force-vs-distance curve measurements. Firstly, the data indicate that substrate types have different effects on cellular morphology of RBC. RBC presented the typical biconcave shape on mica, whereas either the biconcave shape or flattened shape was evident on glass. The mean volume of RBCs on mica was significantly larger than that of cells on glass. Surprisingly, the adhesive property of RBC membrane surfaces was substrate type-independent (the adhesive forces were statistically similar on glass and mica). With time lapse, the changes in cell volume and adhesive force of RBC under the controlled room-temperature condition were similar to those under the uncontrolled outdoor-environmental condition. Under the controlled low-temperature condition, however, the changes in cell volume occurred mainly due to the collapse of RBCs, and the curves of adhesive force showed the dramatic alternations in viscoelasticity of RBC. Taken together, the AFM detections on the time-dependent, substrate type-dependent, environment (temperature/humidity)-dependent changes in morphology and surface viscoelasticity of RBC imply a potential application of AFM in forensic medicine or investigations, e.g., estimating age of bloodstain or death time.     

对氨基二苯甲酮光吸收和光反应活性的含时密度泛函研究

利用含时密度泛函理论研究了对氨基二苯甲酮(p-ABP )的气液相吸收光谱性质．结果表明，p-ABP单重态的性质随着溶剂极性的变化发生明显的改变．在极性溶剂乙腈、甲醇、乙醇、二甲亚砜和二甲基甲酰胺中，S1态是产生于π→π*跃迁的电荷转移态；在非极性溶剂环己烷和苯中，S1态是产生于n→π*跃迁的局域激发态．对于p-ABP三重态的计算结果表明，无论是极性溶剂中还是非极性溶剂中T1态都具有π→π*构型．不同溶剂中激发态构型和跃迁能的变化情况表明，对应于n→π*跃迁的吸收光谱随着溶剂极性的增加出现明显的蓝移，对应于π→π*跃迁的吸收光谱则随溶剂极性的增加出现明显红移．通过对计算结果进行分析，讨论了对氨基二苯甲酮三重态量子产率在不同溶剂中的变化情况和它在氢提取反应中表现出低光还原反应活性原因．     

Compensating for frequency shifts in modulation transfer spectroscopy caused by residual amplitude modulation

Residual amplitude modulation (RAM) distorts saturated absorption signals, limiting the accuracy of optical frequency references based on modulation transfer spectroscopy (MTS). Described here are two independent means by which RAM is produced in these references: (1) by the modulator and (2) when the overlap of the optical fields in the saturable absorber is asymmetric. Methods to vary RAM generated by either mechanism will be outlined and these will be used to show how RAM arising from one effect can be cancelled by the other. A theoretical treatment of MTS signals in references containing RAM is given and used to evaluate the level of signal distortion allowing the conditions for RAM cancellation to be determined. This technique is applied to improve the frequency accuracy of a reference by an order of magnitude.     

Inhibition of modulation instability in lasers by noise

It is shown that additive noise can inhibit modulation instability in laser equations of motion. A related self-starting condition for pulsation is obtained by employing a fluctuation--dissipation relation between noise and losses and a statistical mechanics approach. Entropy considerations are shown to play a crucial role. The quantum limit for self-starting is estimated.     

Equine estrogens differentially inhibit DNA fragmentation induced by glutamate in neuronal cells by modulation of regulatory proteins involved in programmed cell death

Background  

Recent data indicate that excitotoxicity of high levels of neurotransmitter glutamate may be mediated via programmed cell death (apoptosis) and that it can be prevented in HT22 mouse hippocampal cells by various equine estrogens with Δ⁸,17β-estradiol (Δ⁸,17β-E₂) being the most potent. In order to delineate the mechanism(s), glutamate-induced cell death of HT22 cells was assessed by measuring (a) DNA fragmentation in the presence or absence of 11 equine estrogens (components of the drug CEE); (b) cell death and (c) levels of anti-apoptotic (Bcl-2) and proapoptotic (Bax) proteins in the presence or absence of two equine estrogens, Δ⁸,17β-E₂ and 17β-estradiol (17β-E₂) by LDH release assay and Western blot analysis respectively.     

质子与羟基碰撞的含时密度泛函理论研究

采用将含时密度泛函理论和分子动力学非绝热耦合的方法,研究了不同入射速度下质子与羟基碰撞的反应动力学.计算了碰撞前后质子动能和羟基动能的变化及羟基电子和质子的运动.计算结果表明,质子沿垂直羟基分子轴方向入射时,质子与羟基碰撞后,质子被反弹且动能损失并俘获了羟基中氧的一部分电子,而丢失部分电子的羟基则获得动能以伸缩振动的形式向计算边界平动.随着入射质子的初动能增加,质子从羟基中俘获的电子增多,碰撞后羟基的键长变长,羟基振动变强而伸缩振动频率降低.此外,还发现质子的入射方向对碰撞过程的激发动力学有很大的影响.质子从不同的方向入射时,质子的入射初动能越大,其损失的动能越多且损失的动能与入射初动能呈线性关系,而入射方向对质子动能损失的影响很小.在质子入射初动能较低(小于25 eV)的情况下,羟基获得的动能与质子入射初动能呈线性关系且与入射方向无关;在质子入射初动能较高(大于25 eV)时,当质子沿羟基分子轴方向入射时,羟基动能的增量远大于质子沿垂直于羟基分子轴方向入射时羟基动能的增量.     

Time-dependent close-coupling calculations of dielectronic capture in He

We report on the first time-dependent close-coupling calculation of dielectronic capture into a doubly excited state of a two-electron atom. An incoming electron is represented by a Gaussian wave packet which collides with singly ionized helium in its ground state. The close-coupling equations describe the propagation of the total compound wave function on a two-dimensional radial lattice. By projecting this wave function onto a doubly excited state of neutral helium, we can determine the probability amplitude for dielectronic capture into one of these states and the subsequent autoionization from it.     

Time-dependent response of interface states determined by using differential isothermal transient spectroscopy

A method based on the differential analysis of the isothermal transients is proposed to study the dynamical properties of the charging and discharging of interface states, and several possibilities of using this method are shown. The results obtained in SiO₂/Si and Si₃N₄/SiO₂/Si samples are in agreement with the existence of a spatial and energy distribution of interface states within the insulator. From the experimental data, the concentration of traps within the insulator at 35 Å is estimated to be 5×10⁹ cm^-2 eV^-1, with a tunneling cross section 10^-19 cm², at E_c-E ≈ 0.2 eV.     

Copropagation of two pulses of different frequencies and modulation instabilities induced by cross-phase modulation in metamaterials

Nonlinear coupled equations describing the copropagation of two light pulses of different central frequencies in metamaterials (MMs) are derived. Based on the derived equations and the Drude model for dispersive MMs, the modulation instabilities (MIs) induced by cross-phase modulation (XPM) for different combination of the signs of refractive index experienced by the two optical pulses, respectively, are analyzed. It is shown that, in the absence of group-velocity mismatch, the property of MI only depends on the sign of group-velocity dispersion the two pulses experience, irrespective of the sign of refractive index. The group-velocity mismatch plays an important role in the occurrence of MI, especially when the central frequencies of the two pulses near the electric or magnetic plasma frequency of the MM. The theoretical results are confirmed by numerical simulations.     

Visualization of human umbilical vein endothelial cells by acoustic microscopy

The morphology and acoustic properties of the human umbilical vein endothelial cells (HUVECs) were evaluated using a scanning acoustic microscope system. HUVECs were cultured for 4 days and exposed to the endotoxin for 4 h. The frequency of the scanning acoustic microscope was variable between 100 and 210 MHz. By changing the measuring frequency, ultrasonic amplitude and phase were measured and the quantitative value of attenuation was calculated. Before and after endotoxin stimuli, HUVECs were observed by scanning acoustic microscopy and the attenuation was measured. The acoustic images were successfully obtained to identify the outer shape of the HUVEC and the location of the nucleus in the cell. The attenuation of the nucleus is higher than that of the cytoplasm. The attenuation of the cytoplasm was increased and became inhomogeneous after endotoxin exposure. This finding would be related to the change of F-actin filaments, which is the main component of the cytoskeleton. Scanning acoustic microscopy is useful for assessing the cellular viscoelastic properties since it can detect both the morphological and acoustic changes without contacting the cellular surface.     

Amplitude modulation of turbulence noise by voicing in fricatives

The two principal sources of sound in speech, voicing and frication, occur simultaneously in voiced fricatives as well as at the vowel-fricative boundary in phonologically voiceless fricatives. Instead of simply overlapping, the two sources interact. This paper is an acoustic study of one such interaction effect: the amplitude modulation of the frication component when voicing is present. Corpora of sustained and fluent-speech English fricatives were recorded and analyzed using a signal-processing technique designed to extract estimates of modulation depth. Results reveal a pattern, consistent across speaking style, speaker, and place of articulation, for modulation at fo to rise at low voicing strengths and subsequently saturate. Voicing strength needed to produce saturation varied 60-66 dB across subjects and experimental conditions. Modulation depths at saturation varied little across speakers but significantly for place of articulation (with [z] showing particularly strong modulation) clustering at approximately 0.4-0.5 (a 40%-50% fluctuation above and below unmodulated amplitude); spectral analysis of modulating signals revealed weak but detectable modulation at the second and third harmonics (i.e., 2fo and 3fo).     

Light by light modulation in semiconductor doped glass

Fifty percent modulation was observed in Schott Glass OG530 semiconductor doped filter glass with a c.w. argon-ion laser. Laser-induced clearing and darkening were also detected, the balance between them being dependent on sample temperature, modulation frequency and light intensity.