Oligodendrocyte precursor cells differentially expressing Nogo-A but not MAG are more permissive to neurite outgrowth than mature oligodendrocytes

Grafting oligodendrocyte precursor cells (OPCs) has been used as a strategy to repair demyelination of the central nervous system (CNS). Whether OPCs can promote CNS axonal regeneration remains to be tested. If so, they should be permissive to axonal growth and may express less inhibitory molecules on their surface. Here we examined the expression of two oligodendrocyte-associated myelin inhibitors Nogo-A and myelin-associated glycoprotein (MAG) during oligodendrogliogenesis and tested their abilities to promote neurite outgrowth in vitro. Whereas the intracellular domain of Nogo-A was consistently expressed throughout oligodendrocyte differentiation, MAG was expressed only at later stages. Furthermore, the membrane-associated extracellular domain of Nogo-A was not expressed in OPCs but expressed in mature oligodendrocytes. In a dorsal root ganglion (DRG) and OPC/oligodendrocyte co-culture model, significantly greater DRG neurite outgrowth onto OPC monolayer than mature oligodendrocyte was found (1042 ± 123 vs. 717 ± 342 micrometer; p = 0.011). Moreover, DRG neurites elongated as fasciculated fiber tracts and contacted directly on OPCs (133 ± 37 cells/fascicle). In contrast, few, if any, direct contacts were found between DRG neurites and mature oligodendrocytes (5 ± 3 cells/fascicle, p < 0.001). In fact, acellular spaces were found between neurites and surrounding mature oligodendrocytes in contrast to the lack of such spaces in OPC/DRG coculture (51.1 ± 16.5 vs. 2.4 ± 3.9 micrometer; p < 0.001). Thus, OPCs expressing neither extracellular domain of Nogo-A nor MAG are significantly more permissive than mature oligodendrocytes expressing both. Grafting OPCs may thus represent a feasible strategy to foster CNS axonal regeneration.     

Results of the Combined U.S. Multicenter Pivotal Study and the Continuing Access Study of the Nit-Occlud PDA Device for Percutaneous Closure of Patent Ductus Arteriosus

ObjectivesThis study aimed to compare the efficacy and safety of the Nit-Occlud PDA device (PFM Medical, Cologne, Germany) to benchmarks designed as objective performance criteria (OPC).BackgroundThe Nit-Occlud PDA is a nitinol coil-type patent ductus arteriosus (PDA) occluder with a reverse cone configuration, which is implanted using a controlled delivery system.MethodsPatients with <4-mm minimum diameter PDA were prospectively enrolled in the Pivotal and the Continuing Access Studies from 15 sites in the United States and were followed up for 12 months post-procedure. Investigator-reported outcomes were compared to OPC including a composite success criterion, efficacy criteria of successful closure (clinical and echocardiographic), and safety criteria incidence of adverse events (serious and of total).ResultsThe Pivotal Study enrolled patients between November 1, 2002 and October 31, 2005, and the Continuing Access Study enrolled additional patients between September 1, 2006 and October 31, 2007. A total of 357 patients were enrolled, and 347 had successful device implantations. After 12 months, 96.8% had complete echocardiographic closure (OPC = 85%) and 98.1% had clinical closure (OPC = 95%). There were no deaths or serious adverse events (OPC = 1%). The total adverse event rate was 4.7% (OPC = 6%). Composite success was 95.1% in the study patients (OPC = 80%).ConclusionsClosure of small- and medium-sized PDA with the Nit-Occlud PDA is effective and safe when compared with OPC.     

基于OPC 技术的医院呼叫系统设计

为了更好地将呼叫系统融入医院集成管理系统,在OPC接口技术的基础上,设计了一种基于单片机的两线制医院呼叫系统.该系统提供OPC接口,可以方便地利用OPC技术实现数据传输;系统采用二线制,所有分机、紧急呼叫分机和门灯皆并联其上,简化了设计,同时使得安装、维护非常方便.系统实时性强、可靠性高、成本低、安装方便,具有很强的实用价值.     

Prevalence of oral and blood oncogenic human papillomavirus biomarkers among an enriched screening population: Baseline results of the MOUTH study

Background

Human papillomavirus (HPV)-related oropharyngeal cancer screening is being explored in research studies, but strategies to identify an appropriate population are not established. The authors evaluated whether a screening population could be enriched for participants with oncogenic HPV biomarkers using risk factors for oral HPV.

Methods

Participants were enrolled at Johns Hopkins Hospitals and Mount Sinai Icahn School of Medicine. Eligible participants were either men aged 30 years or older who had two or more lifetime oral sex partners and a personal history of anogenital dysplasia/cancer or partners of patients who had HPV-related cancer. Oral rinse and serum samples were tested for oncogenic HPV DNA, RNA, and E6 or E7 antibodies, respectively. Participants with any biomarker were considered at-risk.

Results

Of 1108 individuals, 7.3% had any oncogenic oral HPV DNA, and 22.9% had serum antibodies for oncogenic HPV E6 or E7. Seventeen participants (1.5%) had both oral and blood biomarkers. HPV type 16 (HPV16) biomarkers were rarer, detected in 3.7% of participants, including 20 with oral HPV16 DNA and 22 with HPV16 E6 serum antibodies (n = 1 had both). In adjusted analysis, living with HIV (adjusted odds ratio, 2.65; 95% CI, 1.60–4.40) and older age (66–86 vs. 24–45 years; adjusted odds ratio, 1.70; 95% CI, 1.07–2.70) were significant predictors of being at risk. Compared with the general population, the prevalence of oral HPV16 (1.8% vs. 0.9%), any oncogenic oral HPV DNA (7.3% vs. 3.5%), and HPV16 E6 antibodies (2.2% vs. 0.3%) was significantly elevated.

Conclusions

Enrichment by the eligibility criteria successfully identified a population with higher biomarker prevalence, including HPV16 biomarkers, that may be considered for screening trials. Most in this group are still expected to have a low risk of oropharyngeal cancer.     

神经节苷酯对新生大鼠HIBD脑白质OPC死亡通路阻断作用的研究

目的探讨体外注射神经节苷酯对新生大鼠HIBD后对脑细胞凋亡的影响,以及对脑白质opc死亡通路阻断所体现的脑保护作用。方法新生大鼠30只随机分为：假手术组（n=10）、HIBD组（n=10）、HIBD＋神经节苷酯治疗组（n=10）.HIBD组和HIBD＋神经节苷酯治疗组制作HIBD模型。HIBD＋神经节苷酯治疗组每只新生大鼠分别腹腔注射30 mg/kg神经节苷酯,每日1次,连续6d。7日龄时断头取脑,制作脑片,计算每张脑片中OPC的凋亡数目,进行统计学处理,比较组间差异。结果 HIBD后,HIBD组较假手术组OPC的凋亡数目明显增多。具有统计学意义（P〈0.01,P=0.0001）HIBD＋神经节苷酯治疗组较HIBD组OPC的凋亡数目明显减少,具有统计学意义（P〈0.01,P=0.0005）。结论HIBD后新生大鼠OPC的凋亡数目明显增多。神经节苷酯早期干预后可明显减少HIBD后新生大鼠OPC的凋亡数目。从而证明神经节苷酯对新生大鼠HIBD脑白质OPC死亡通路的阻断作用具有一定的效力。     

Olanzapine stimulates proliferation but inhibits differentiation in rat oligodendrocyte precursor cell cultures

In the developing brain, oligodendrocyte progenitor cells (OPCs) proliferate, migrate, and differentiate into mature oligodendrocytes (OLs) capable of myelinating axons. Recently, OPCs have been identified as an abundant and widespread population in the adult as well as in the developing animal. Current research indicates that these OPCs in the adult brain can proliferate and differentiate into myelinating OLs, albeit with different potentialities from those in developing animals.Multiple lines of evidence, from neuroimaging, postmortem, and genetic association studies, have implicated OL and myelin dysfunction in the pathogenesis of schizophrenia. If altered OL function is involved in pathogenesis, OPCs may thus respond to antipsychotic drugs during the recovery process. In the present study, we used primary OPC cultures from optic nerve of newborn Wistar rat pups to investigate the direct effects of haloperidol (HPD; a typical antipsychotic) and olanzapine (OLZ; an atypical antipsychotic) on the proliferation and differentiation of OPCs. Our results showed that 1) OLZ treatment significantly increased the number of viable OPCs when compared to HPD treatment at relatively high concentrations, 2) OLZ treatment suppressed the expression of myelin basic protein (MBP), and to a greater extent than HPD treatment, and 3) these pharmacological effects may be mediated via the ERK signaling pathway.Our findings suggest a glial mechanism for the antipsychotic action of OLZ, and a role for oligodendrocyte-lineage cells in the pathogenesis and treatment of schizophrenia.     

Energy metabolism in adult neural stem cell fate

The adult mammalian brain contains a population of neural stem cells that can give rise to neurons, astrocytes, and oligodendrocytes and are thought to be involved in certain forms of memory, behavior, and brain injury repair. Neural stem cell properties, such as self-renewal and multipotency, are modulated by both cell-intrinsic and cell-extrinsic factors. Emerging evidence suggests that energy metabolism is an important regulator of neural stem cell function. Molecules and signaling pathways that sense and influence energy metabolism, including insulin/insulin-like growth factor I (IGF-1)-FoxO and insulin/IGF-1-mTOR signaling, AMP-activated protein kinase (AMPK), SIRT1, and hypoxia-inducible factors, are now implicated in neural stem cell biology. Furthermore, these signaling modules are likely to cooperate with other pathways involved in stem cell maintenance and differentiation. This review summarizes the current understanding of how cellular and systemic energy metabolism regulate neural stem cell fate. The known consequences of dietary restriction, exercise, aging, and pathologies with deregulated energy metabolism for neural stem cells and their differentiated progeny will also be discussed. A better understanding of how neural stem cells are influenced by changes in energy availability will help unravel the complex nature of neural stem cell biology in both the normal and diseased state.     

Glia–neuron interactions in the mammalian retina

The mammalian retina provides an excellent opportunity to study glia–neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K⁺ uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.