脑科学与量子理论

简要回顾了生物学与物理学之间的紧密关系,其中包括人工神经网络的经典物理模型和脑的某些量子理论;概要综述了细胞骨架微管的结构和生物功能及有关近期理论研究。注意到微声是细胞和神经元中重要的组成和功能单元,进而以较大篇幅介绍了近期关于微管的理论研究工作,特别是基于量子场论中两能级系统的赝自旋模型,对微管管壁上电子的动力学行为作了较深入的探讨;此外,基于量子场论,对微管中的水分子系统可能存在微波受激辐射也作了阐述。The present paper briefly reviews the relationship between biology and physics, especially including the classical physics models for the artificial neuron networks, some quantum theories for brains, and simply describes the structures and functions of cytoskeletal microtubules （MTs） in cells and some recent theoretical studies on MTs.Noting MTs are the important components and function units in cells and neurons, furthermore, the paper lays emphasis on our recent theoretical work on MTs. Particularly, based on the pseudo-spin quantum theory, the dynamic behavior of electrons on the MT wall has been discussed in some detail. Based on the quantum field theory, it has been described that the maser radiation might exist in the water molecular system within the MT.     

Automated data processing of [1H-decoupled] 13C MR spectra acquired from human brain in vivo

In clinical 13C infusion studies, broadband excitation of 200 ppm of the human brain yields 13C MR spectra with a time resolution of 2-5 min and generates up to 2000 metabolite peaks over 2h. We describe a fast, automated, observer-independent technique for processing [1H-decoupled] 13C spectra. Quantified 13C spectroscopic signals, before and after the administration of [1-13C]glucose and/or [1-13C]acetate in human subjects are determined. Stepwise improvements of data processing are illustrated by examples of normal and pathological results. Variation in analysis of individual 13C resonances ranged between 2 and 14%. Using this method it is possible to reliably identify subtle metabolic effects of brain disease including Alzheimer's disease and epilepsy.     

A Calixarene Assembly Strategy of Combined Anti-Neuroinflammation and Drug Delivery Functions for Traumatic Brain Injury Therapy

Excessive inflammatory reaction aggravates brain injury and hinders the recovery of neural function in nervous system diseases. Microglia, as the major players of neuroinflammation, control the progress of the disease. There is an urgent need for effective non-invasive therapy to treat neuroinflammation mediated by microglia. However, the lack of specificity of anti-inflammatory agents and insufficient drug dose penetrating into the brain lesion area are the main problems. Here, we evaluated a series of calixarenes and found that among them the self-assembling architecture of amphiphilic sulfonatocalix[8]arene (SC8A12C) had the most potent ability to suppress neuroinflammation in vitro and in vivo. Moreover, SC8A12C assemblies were internalized into microglia through macropinocytosis. In addition, after applying the SC8A12C assemblies to the exposed brain tissue, we observed that SC8A12C assemblies penetrated into the brain parenchyma and eliminated the inflammatory factor storm, thereby restoring neurobiological functions in a mouse model of traumatic brain injury.     

Promising Chemotherapy for Malignant Pediatric Brain Tumor in Recent Biological Insights

Brain tumors are the most widespread malignancies in children around the world. Chemotherapy plays a critical role in the treatment of these tumors. Although the current chemotherapy process has a remarkable outcome for a certain subtype of brain tumor, improving patient survival is still a major challenge. Further intensive treatment with conventional non-specific chemotherapy could cause additional adverse reactions without significant advancement in survival. Recently, patient derived brain tumor, xenograft, and whole genome analysis using deep sequencing technology has made a significant contribution to our understanding of cancer treatment. This realization has changed the focus to new agents, targeting the molecular pathways that are critical to tumor survival or proliferation. Thus, many novel drugs targeting epigenetic regulators or tyrosine kinase have been developed. These selective drugs may have less toxicity in normal cells and are expected to be more effective than non-specific chemotherapeutics. This review will summarize the latest novel targets and corresponding candidate drugs, which are promising chemotherapy for brain tumors according to the biological insights.     

Derivative temporal clustering analysis: detecting prolonged neuronal activity

Temporal clustering analysis (TCA) and independent component analysis (ICA) are promising data-driven techniques in functional magnetic resonance imaging (fMRI) experiments to obtain brain activation maps in conditions with unknown temporal information regarding the neuronal activity. Although comparable to ICA in detecting transient neuronal activities, TCA fails to detect prolonged plateau brain activations. To eliminate this pitfall, a novel derivative TCA (DTCA) method was introduced and its algorithms with different subtraction intervals were tested on simulated data with a pattern of prolonged plateau brain activation. It was found that the best performance of DTCA method in generating functional maps could be obtained if the subtraction interval is equal to or larger than the length of the rising time of the fMRI response. The DTCA method and its theoretical predication were further investigated and validated using in vivo fMRI data sets. By removing the limitations in the previous TCA, DTCA has shown its powerful capability in detecting prolonged plateau neuronal activities.     

柠檬醛长时程嗅觉吸入的脑功能活动MEMRI研究

本文使用设计的嗅觉吸入装置使大鼠吸入挥发性柠檬醛或无气味空气，之后使用锰增强磁共振成像（MEMRI）的方法，观察长时程（24 h）吸入柠檬醛之后，大鼠脑功能活动变化情况．基于体素分析和感兴趣区（ROI）分析结果显示，与对照组相比，长时程吸入柠檬醛组大鼠伏隔核中心部（AcbC）、嗅小球层（GL）等脑区功能活动增强；而该组大鼠视皮层（VC）、听觉皮层（AC）、压后皮层（RSC）等脑区锰累积显著减少．且长时程吸入柠檬醛之后，大鼠脑区GL与关联的脑区功能相关性显著增强．从而表明MEMRI可用于长时程嗅觉吸入刺激的脑功能研究，并极具应用前景．     

Low-Spin Ferriheme Models of the Cytochromes: Correlation of Molecular Structure with EPR and Mössbauer Spectral Parameters

The electronic properties of the intermetallic compound HfCo₃B₂ were investigated using combined TDPAC measurements and first principles LAPW calculations. The V _zz value at the hafnium site is determined from dominant positive p–p contribution, with less than 20%, negative s–d and d–d contributions. Based on the calculated density of state (DOS) at 0 K, a band contribution (γ _band) of 7.26 (mJ/mol/K²) to the value of the electronic specific heat coefficient (γ) was obtained. This relatively low γ _band value is attributed to the hybridization between hafnium d-states, boron 2p-states and cobalt 3d-states, formed at the energy interval below E _Fermi. This hybridization, together with the dip in the DOS around E _Fermi, implies a possible reduction of the low temperature magnetic moment in this compound.     

Proton nuclear magnetic resonance spectra of brain tumors

Proton nuclear magnetic resonance (NMR) spectra were successfully measured in human brain tumor tissues and experimental rat brain tumors. The investigation was performed on clinical materials which consisted of tissue from one normal brain and 36 brain tumors. Normal rat brain tissue and rat glioma implanted in the brain were also analysed. NMR measurements were carried out at the resonance frequency of 99.54 MHz. The proton NMR spectrum of the normal brain consisted of one broad component and eight superimposed sharp peaks. The sharp peaks obtained from the brain tumors varied from those of the normal brain. A decrease in the signal intensity from N-acetyl aspartate was the most common finding in all tumors. Spectral patterns were similar within the same histological types, but varied among the different types. Therefore, ¹H-NMR spectra might indicate the metabolism characteristic of each tumor type which would be invaluable for clinical differential dagnosis of brain tumors.     

Superfine Magnetic Resonance Imaging of the Cerebrovasculature Using Self‐Assembled Branched Polyethylene Glycol–Gd Contrast Agent

Magnetic resonance angiography is an attractive method for the visualization of the cerebrovasculature, but small‐sized vessels are hard to visualize with the current clinically approved agents. In this study, a polymeric contrast agent for the superfine imaging of the cerebrovasculature is presented. Eight‐arm polyethylene glycol with a molecular weight of ≈17 000 Da conjugated with a Gd chelate and fluorescein (F‐8‐arm PEG‐Gd) is used. The relaxivity rate is 9.3 × 10⁻³m ⁻¹ s⁻¹, which is threefold higher than that of free Gd chelate. Light scattering analysis reveals that F‐8‐arm PEG‐Gd is formed by self‐assembly. When the F‐8‐arm PEG‐Gd is intravenously injected, cerebrovasculature as small as 100 µm in diameter is clearly visualized. However, signals are not enhanced when Gd chelate and Gd chelate‐conjugated 8‐arm PEG are injected. Furthermore, small vasculature around infarct region in rat stroke model can be visualized. These results suggest that F‐8‐arm PEG‐Gd enhances the MR imaging of cerebrovasculature.