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.     

肝门部胆管癌的分型分期系统及其临床应用价值

肝门部胆管癌（hilar cholangiocarcinoma，HC）分型和分期系统较为庞杂，包括改良Bismuth-Corlette分型，Gazzaniga T分期，Blumgart T分期，美国纪念Sloan-Kattering癌症中心（Memorial Sloan Katering Cancer Center，MSKCC）T分期，Mayo分期系统，美国癌症联合委员会（American Joint Committee on Cancer，AJCC）和国际抗癌联盟（International Union Against Cancer，UICC）联合发布的TNM分期，欧洲肝胆胰协会分期（Consensus classification from the European Hepato-Pancreato-Biliary Association，EHPBA），以及日本肝胆胰外科学会（Japanese Society of Hepato-Biliary-Pancreatic Surgery，JSHBPS）分期，各分期系统所包含的内容差异较大，各具特色和优缺点，本文就HC常见的分型和分期系统及其在临床中的应用价值做一综述。     

Comparison of guidelines and consensus articles on the management of patients with acne with oral isotretinoin

Guidelines and consensus on the management of patients with acne aim to give evidence-based, expert-group recommendations. This review compares current guidelines and consensus articles to provide a compilation of recommendations on the treatment of acne with oral isotretinoin. Ten common, relevant, clinical questions are addressed, based on published recommendations, including the indications of isotretinoin, the proposed daily dose, the cumulative isotretinoin dose and the laboratory monitoring needed. Recommendations on special considerations are also addressed, including the timing of procedures and the question of an association of depression or inflammatory bowel disease with isotretinoin. A major limitation is the use of different classification systems for acne across guidelines. The recommended daily dose ranges from 0.3 to 0.5 mg/kg in the European guidelines to up to 1 mg/kg in the US guidelines. A specific duration of treatment of at least 6 months is only recommended in the European guidelines. All guidelines report the need of strict pregnancy prevention measures. The European, French and US guidelines recommend to monitor for symptoms of depression. Important clinical questions that are inconsistently addressed in guidelines include the age indication, the recommendation for a cumulative dose, the timing of procedures, the association of isotretinoin with IBD, the recommendation for preventing acne flares and for appropriate laboratory monitoring. These topics should be clearly included in the recommendations of guidelines as they are often raised in everyday clinical practice.