Reading the unique DNA methylation landscape of the brain: Non-CpG methylation,hydroxymethylation, and MeCP2

DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.     

A multi-institutional experience in vascular Ehlers-Danlos syndrome diagnosis

ObjectiveVascular Ehlers-Danlos syndrome (vEDS) is a rare disorder and 1 of 13 types of EDS. The syndrome results in aortic and arterial aneurysms and dissections at a young age. Diagnosis is confirmed with molecular testing via skin biopsy or genetic testing for COL3A1 pathogenic variants. We describe a multi-institutional experience in the diagnosis of vEDS from 2000 to 2015.MethodsThis is a multi-institutional cross-sectional retrospective study of individuals with vEDS. The institutions were recruited through the Vascular Low Frequency Disease Consortium. Individuals were identified using the International Classification of Diseases-9 and 10-CM codes for EDS (756.83 and Q79.6). A review of records was then performed to select individuals with vEDS. Data abstraction included demographics, family history, clinical features, major and minor diagnostic criteria, and molecular testing results. Individuals were classified into two cohorts and then compared: those with pathogenic COL3A1 variants and those diagnosed by clinical criteria alone without molecular confirmation.ResultsEleven institutions identified 173 individuals (35.3% male, 56.6% Caucasian) with vEDS. Of those, 11 (9.8%) had nonpathogenic alterations in COL3A1 and were excluded from the analysis. Among the remaining individuals, 86 (47.7% male, 68% Caucasian, 48.8% positive family history) had pathogenic COL3A1 variants and 76 (19.7% male, 19.7% Caucasian, 43.4% positive family history) were diagnosed by clinical criteria alone without molecular confirmation. Compared with the cohort with pathogenic COL3A1 variants, the clinical diagnosis only cohort had a higher number of females (80.3% vs 52.3%; P < .001), mitral valve prolapse (10.5% vs 1.2%; P = .009), and joint hypermobility (68.4% vs 40.7%; P < .001). Additionally, they had a lower frequency of easy bruising (23.7% vs 64%; P < .001), thin translucent skin (17.1% vs 48.8%; P < .001), intestinal perforation (3.9% vs 16.3%; P = .01), spontaneous pneumothorax/hemothorax (3.9% vs 14%, P.03), and arterial rupture (9.2% vs 17.4%; P = .13). There were no differences in mortality or age of mortality between the two cohorts.ConclusionsThis study highlights the importance of confirming vEDS diagnosis by testing for pathogenic COL3A1 variants rather than relying on clinical diagnostic criteria alone given the high degree of overlap with other forms genetically triggered arteriopathies. Because not all COL3A1 variants are pathogenic, the interpretation of the genetic testing results by an individual trained in variant assessment is essential to confirm the diagnosis. An accurate diagnosis is critical and has serious implications for lifelong screening and treatment strategies for the affected individual and family members.     

脑后部可逆性脑病综合征(PRES)的临床MR诊断

目的：探讨MR对PRES的临床诊断价值。方法应用3.0 T MR对30例PRES患者进行常规扫描，其中19例同时行MRA检查，13例行MRV检查。结果 PRES病变主要累及顶枕叶，双侧基本对称；病变主要位于脑白质内，也可累及其它部位。PRES病变的特点是呈长T 1长T 2信号，边缘不清，无明显占位效应。MRA及MRV均无异常发现。结论 MR对PRES可以作出准确诊断，对临床有重要的指导意义。     

A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study

ObjectiveWe aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system.MethodsIn order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference.ResultsWe found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings.ConclusionIn this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application.SignificanceEstablished and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.     

从中医角度探讨多囊卵巢综合征的发生与肺胃的相关性

对于“多囊卵巢综合征”中医病位的认识,学者们众说纷纭,主要涉及肺、肝、脾、肾、胃、冲任等。本文对其病位在“肺”“胃”这一观点提出质疑,并以多囊卵巢综合征现代文献资料为主要研究对象,确定多囊卵巢综合征的病变脏腑,提取多囊卵巢综合征的主要症状,总结多囊卵巢综合征的核心病机,从而探究多囊卵巢综合征的病位,讨论本病的发生与肺胃的相关性,加深对多囊卵巢综合征的中医认识。     

TLR9在不同胎龄新生儿脐血中的表达变化

目的 通过观察早产儿不同胎龄Toll样受体9（TLR9）的表达，探讨早产儿免疫功能低下的机制。方法 采集2010年7月至2014年6月在上海市嘉定区妇幼保健院产科出生的活产新生儿的脐血229份，按胎龄分为4组，28~31周组，31~34周组，34~37周组，≥37周组，采用流式细胞术和实时荧光定量PCR方法，分别检测其TLR9的蛋白和mRNA表达情况，了解其与胎龄之间的关系，并分析mRNA和蛋白表达间的相关性。结果 TLR9阳性细胞率在28~31周组，31~34周组，34~37周组，≥37周组分别为（15.93±6.23）%，（11.63±6.70）%，（13.66±6.88）%，（20.51±12.06）%；其在胎龄28~31周较高，至31~34周逐渐下降至最低，两组差异有统计学意义（P<0.05）；34~37周后TLR9阳性细胞率表达逐渐升高，至≥37周达最高，两胎龄组比较，差异具有统计学意义（P<0.05）。31~37周间新生儿脐血TLR9阳性细胞率与胎龄呈正相关（r=0.273，P=0.006）。TLR9 mRNA表达在28~31周组，31~34周组，34~37周组，≥37周组分别为（4.95±3.44）%，（8.89±8.49）%，（13.91±10.92）%，（7.19±7.11）%；其在28~36周逐渐升高，与胎龄呈正相关（r=0.355，P< 0.001）。≥37周TLR9 mRNA表达量下降，该值虽高于28~31周，但差异无统计学意义（P>0.05）。相关性分析表明，同胎龄时期同样本新生儿的TLR9 mRNA和TLR9阳性细胞率之间存在负相关（r=-0.227，P=0.011）。结论 TLR9阳性细胞率和TLR9 mRNA表达在不同胎龄组新生儿间有差异，TLR9阳性细胞率表达在31~37周间随着胎龄的增加而增加，TLR9 mRNA在28~36周间随着胎龄的增加而增加。