Temporal-spatial ablation of neural crest in the mouse results in cardiovascular defects.

Neural crest cells are thought to play a critical role in human conotruncal morphogenesis and dysmorphogenesis. Much of our understanding of the contribution of neural crest to cardiovascular patterning comes from ablation and transplantation experiments in avian species. Although fate mapping experiments in mice suggests a conservation of function, the functional requirement for neural crest in cardiovascular development in mammals has not been formally tested. We used a novel two component genetic system for the temporal-spatial ablation of neural crest in the mouse. Affected embryos displayed a spectrum of cardiovascular outflow tract defects and aortic arch patterning abnormalities. We show that the severity of the cardiovascular phenotype is directly related to the level and extent of neural crest ablation. This is the first report of cardiac neural crest ablation in mammals, and it provides important insight into the role of the mammalian neural crest during cardiovascular development.     

Stochastic and Coherence Resonance in an In Silico Neural Model

We show that it is possible for chaotic systems to display the main features of stochastic and coherence resonance. In particular, a model of coupled nonlinear oscillators which emulates the transmembrane voltage activities in CA3 neurons, operating in a chaotic regime and in the presence of noise, can exhibit coherence resonance and stochastic resonance. Certain firing frequencies become more "rhythmic" for some optimal values of noise intensity. The effect of noise in different coupling pathways is investigated. We found that the effect of coherence resonance and stochastic resonance are more prominent if noise is presented in either electric field or gap junction coupling pathways. Frequency sensitivity of the model is investigated as a preliminary step in illustrating the principles of possible epileptic seizure control strategies using "chaos control" concepts. Significant effects of stochastic resonance are observed in the 4-8 Hz range. Weaker effects can be found in the 1-4 Hz and 8-10 Hz ranges whereas 0.5 Hz does not exhibit any resonance phenomenon. Our results suggest that: (a) Stochastic resonance could enhance the intrinsic 4-8 Hz rhythms in CA3 neurons more prominently via field coupling pathways. It could also help explain why some reported seizure control strategies using pulse-trains would only be effective at 0.5 Hz. (b) Stochastic resonance-like behavior can occur in the gamma range only if noise is presented via chemical synaptic pathways.     

化合物构效关系的模糊极小极大神经网络识别研究

应用模糊极小极大神经网络研究了化合物复杂结构和性能（QSAR）之间的关系，用该法进行几组化合物致癌的识别，结果优于线性回归的方法，对此作出一些分析。     

Pulmonary function changes in asthmatics associated with low-level SO2 and NO2 air pollution, weather, and medicine intake

This paper presents the response in subjects with asthma to gaseous air-pollution levels, weather, and medicine intake as identified by principal-component analysis and neutral network techniques. Pulmonary function measured by respiratory peak-flow rate in nonallergic asthmatics was associated with ambient, low level, air-pollution concentrations of sulphur dioxide and nitrogen dioxide, temperature, relative humidity, and medicine intake. Results from 27 nonallergic asthmatics aged 18–60 years with well-characterized bronchial asthma and regular medical treatment were analyzed from two cities. During an 8-month period, each subject kept a diary table, which included symptoms, lung function (evening peak flow), medicine intake, and tobbaco smoking.
High intake of medicine and high ambient temperatures correspondend to decreased peak flow. The changes in temperature did not occur in situations with low medicine intake. During frost periods, peak-flow values decreased independently of medicine intake and levels of so². During other times, increased levels of so² and no² increased temperature, and increased intake of medicine, and low relative humidity corresponded to synergistically to decreased peak flow at levels above 40μ/m³.     

Malignant peripheral nerve sheath tumor of small round cell type with pleomorphic spindle cell sarcomatous areas

An unusual case of malignant peripheral nerve sheath tumor (MPNST) arising in the posterior mediastinum of a 59-year-old man is reported. Histopathologically, the tumor showed an admixture of a dense proliferation of small round cells resembling a primitive neuroectodermal tumor (PNET) and a pleomorphic spindle cell sarcomatous area. Abortive rosettes, primitive neural tube-like structures, and a few glandular structures were found in the small round cell area. Small round cells were immunoreactive for neural cell adhesion molecule and synaptophysin, but were not immunoreactive for MIC2 and neuron-specific enolase. Pleomorphic spindle cells were occasionally arranged in a storiform pattern and were diffusely immunoreactive for S-100 protein. The MPNST of small round cell type is distinguishable from PNET by its negative immunoreactivity for MIC2, and the present tumor is assumed to be derived from primitive neuroectodermal cells in the peripheral nerve capable of bidirectional (neuron and Schwann cell) differentiation.     

骨髓神经组织定向干细胞的分离培养鉴定

目的:为临床中枢神经系统疾患的细胞移植及组织工程修复周围神经提供一种应用广泛、可来源于自体、无免疫排斥和伦理道德等问题的移植用种子细胞。方法:采用DMEM/F12(1∶1)无血清神经干细胞培养液,通过先贴壁、后悬浮的方法从大鼠骨髓中分离、培养单克隆生长的神经组织定向干细胞(neural tissue-committed stem cells,NTC-SCs),通过免疫细胞化学检测NTCSCs细胞球CXCR4和Nestin蛋白,以及细胞球自然分化后神经元β-TublinⅢ、MAP2ab以及神经胶质细胞CNPase、GFAP等蛋白的表达。结果:NTCSCs细胞球表达神经干细胞标志蛋白Nestin和组织定向干细胞标志蛋白CXCR4;NTCSCs细胞球在含15%胎牛血清的DMEM培养液中可自然分化,免疫荧光显示神经元和神经胶质蛋白β-TublinⅢ、MAP2ab、CNPase、GFAP等标志物阳性。结论:本研究提供了一种操作简便、成本低廉的NTCSCs的分离培养方法,NTCSCs作为种子细胞为脑、脊髓等神经系统疾患和创伤的修复和治疗提供了广阔的应用前景。     

Release of endogenous 5-hydroxytryptamine from the neural and the intermediate lobe of the rat pituitary gland evoked by electrical stimulation of the pituitary stalk

A calcium-dependent release of 5-hydroxytryptamine from the neural and intermediate lobe of the rat pituitary gland has been demonstrated following electrical stimulation of the pituitary stalk with stimulation parameters thought to evoke propagated action potentials. The 5-hydroxytryptamine release from the intermediate lobe was double that from the neural lobe. The mass of the intermediate lobe of the rat is about 80% of that of the neural lobe [Holzbauer, Racké, Mann, Cooper, Cohen, Krause and Sharman (1984) J. Neural Transm. 59, 91-104]. The relatively high overflow of 5-hydroxytryptamine from the intermediate lobe agrees with immunohistochemical studies in which a larger number of 5-hydroxytryptamine fibres were seen in the intermediate lobe than in the neural lobe. The present results have demonstrated that the rat hypophysis contains neuronal 5-hydroxytryptamine. They also suggest that this amine may act as a neurotransmitter substance in the neural and intermediate lobe.     

损毁单侧黑质-纹状体通路的大鼠SVZ、纹状体和黑质神经前体细胞的变化

研究成年大鼠脑室下区 (SVZ)神经前体细胞 (neural precursors)在黑质 -纹状体通路损伤后的反应 ,本研究用 6-羟多巴胺单侧纹状体注射以损毁黑质 -纹状体通路 ,损毁 10 d后腹腔注射 Brd U ,连续 4d,每日两次 ;在 SVZ、纹状体和黑质部位用免疫组化方法检测 Brd U、nestin以及 GFAP阳性细胞。结果显示 :(1) 6-羟多巴胺损毁黑质 -纹状体通路后 ,伤侧 SVZ的 Brd U阳性细胞数明显增多 ,并成簇分布 ;nestin和 GFAP阳性细胞数也增多 ,但以 GF AP阳性细胞增多明显 ;(2 )伤侧纹状体可见大量 Br-d U、GFAP以及少量 nestin阳性细胞分布 ,而健侧只有少量 GFAP阳性细胞 ;(3 )伤侧可见 Brd U阳性细胞在 SVZ和纹状体之间呈条带样分布 ;(4 )伤侧黑质除酪氨酸羟化酶阳性神经元减少外 ,未见 Brd U、GFAP和 nestin阳性细胞表达。上述结果表明 ,6-羟多巴胺损毁黑质 -纹状体通路后 ,SVZ神经前体细胞活动增强 ,有向纹状体迁移的趋势。     

Infrared spectroscopy: A new diagnostic tool in Alzheimer disease

Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and β-amyloid_1–42 proteins to a novel approach – Fourier transformed infrared (FT-IR) spectroscopy – a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. β-Amyloid_1–42 was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/β-amyloid_1–42 quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and β-amyloid_1–42 protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool.     

Screening for coeliac disease as a possible maternal risk factor for neural tube defect

Coeliac disease is an important cause of malabsorption, particularly of folic acid, in adults. We investigated the possibility that it might be a maternal risk factor for neural tube defect (NTD)-associated pregnancy by screening affected mothers using serum endomysial antibody (EmA) which has high sensitivity and specificity for coeliac disease. One (1.6%) of 60 patients was EmA positive and had a diagnosis of coeliac disease confirmed by the finding of villous atrophy on jejunal biopsy. In conclusion, the majority of NTD-associated pregnancies are not associated with maternal coeliac disease and our study is additional evidence that abnormalities of folic acid metabolism rather than absorption are the most important risk factors for NTD. Further studies are needed to determine whether the coeliac disease prevalence among women with NTD-affected pregnancy is higher than that of the general population.