经典Wnt 信号通路在心脏瓣膜发育中的作用

心脏瓣膜的形成是脊椎动物心脏发育过程中的重要环节。心脏瓣膜的发育异常会导致心功能不全,是人类先天性心脏病的常见表征之一。经典Wnt 信号通路在心脏发育的不同时期分别作用于心肌细胞、心内皮细胞以及瓣膜原基细胞的增殖、分化和迁移过程,并调控心内膜垫形成过程中的内皮-间充质细胞转化(EndMT)过程,具有多面性和时效性。该文将总结经典Wnt 信号通路在心脏瓣膜发育领域的最新研究进展,分别阐述经典Wnt 信号通路在不同瓣膜发育阶段中的功能变化,并展示经典Wnt 信号通路与其他瓣膜发育相关的信号通路及表观遗传修饰间的相互关系,最后分析心脏发育后期Wnt 信号通路对瓣膜间充质干细胞发挥潜在功能的作用。     

微小RNA与磷酸肌醇-3激酶／蛋白激酶B信号通路在心脏发育中的作用

微小RNA具有调控细胞增殖、分化和生物体生长发育等功能.磷酸肌醇-3激酶/蛋白激酶B信号通路在细胞增殖、分化和器官组织发育也起重要作用.了解微小RNA与磷酸肌醇-3激酶／蛋白激酶B信号通路分别在心脏发育中的作用及两者之间关系将有助于进一步地阐述心脏发育畸形及其相关疾病的发病机制.     

Notch信号与肺发育

Notch信号是一种进化保守性细胞间的相互作用机制,可影响发育过程中多种细胞的分化、增殖和凋亡,进而决定细胞命运和发育过程,在多种组织和器官的早期发育过程中起中心作用。近年来,有关Notch信号通路在胚胎肺发育发生中的作用已成为国际研究热点。本文就Notch信号的基因结构及     

microRNA-296-5p靶基因的预测及在肺发育中的应用

目的 对rno-microRNA-296-5p（miR-296）靶基因预测并进行相关生物信息学分析,为深入研究miR-296与胎肺发育相关的生物学功能提供理论依据。方法 应用PubMed、Google等信息搜索工具检索miR-296的现有研究,并通过miRBase获取其序列特征以及进化的保守性;利用TargetScan数据库进行miR-296的靶基因预测;并利用DAVID Bioinformatics Resources 6.8数据库对靶基因进行功能富集分析;利用KEGG数据库对靶基因进行信号转导通路分析。结果 已有的文献表明miR-296在许多生物学过程中发挥重要作用,序列在多物种间高度保守。miR-296调控的靶基因参与分子功能、细胞组分和生物学过程等方面,靶基因集合的信号转导通路显著富集于MAPK信号通路、Wnt信号通路、TGF-β信号通路等（均P 结论 通过对miR-296靶基因的生物信息学分析,为研究miR-296在肺发育中的作用提供了功能与机制的线索。     

先天性巨结肠症分子基因学研究进展

先天性巨结肠症是由多种因素导致胚胎期肠神经嵴细胞发育异常而引起的一种小儿外科常见病,多个基因或基因信号通路参与其病理发生过程。迄今为止,人们发现了至少11个与先天性巨结肠症发生相关的易患基因,这些基因的表达异常或相互作用异常可导致神经嵴细胞发育异常,引起先天性巨结肠症。该文就易患基因及其在先天性巨结肠症发生中的作用进行综述。     

MiRNA-126*靶基因预测及其相关信号通路的生物信息学分析

目的：通过对miRNA-126*进行靶基因预测及信号通路生物信息学分析,以期为miRNA-126*靶基因相关实验及其调控肺发育机制的深入研究奠定基础。方法：首先利用microRNA（miRNA）芯片技术分别检测胎龄16 d、19 d和21 d胎鼠肺组织中miRNA-126*的表达水平,进而应用miRGen2.0数据库通过生物信息学方法预测其可能的靶基因,然后对其靶基因集合应用Cytoscape及其插件BiNGO进行功能富集分析（GO-analysis）,最后应用DAVID数据库进行靶基因信号转导通路富集分析（KEGG Pathway analysis）。结果：miRNA-126*表达量在胎龄16 d、19 d和21 d 3组胎肺组织间逐渐上升。miRNA-126*预测靶基因共有422个,其靶基因集合功能富集于葡萄糖醛酸转移酶、糖代谢等分子功能,多细胞器官发育、发育进程等生物学过程及细胞分隔、细胞器界膜等细胞组分上。信号转导通路则显著富集于RNA降解信号通路,以及朊蛋白疾病信号通路中。结论：本研究结果提示miRNA-126*参与了大鼠胎肺发育过程,为今后研究肺发育提供理论基础。     

T-box 转录因子TBX20与心脏发育及人类先天性心脏病的研究进展

近年来,动物研究发现T-box基因家族的一个新成员Tbox20基因在心脏发育过程中起着重要作用.心脏发育与先天性心脏病之间有明显的相关性,提示TBX20基因在人类先天性心脏病的发生过程中可能起着重要作用.但目前关于TBX20基因与人类先天性心脏病相关性的研究甚少.该文综述了TBX20基因的结构、表达、在心脏发育中的功能与途径以及在人类先天性心脏病发生中的最新研究进展.     

T-box 转录因子TBX20与心脏发育及人类先天性心脏病的研究进展

近年来,动物研究发现T-box基因家族的一个新成员Tbox20基因在心脏发育过程中起着重要作用.心脏发育与先天性心脏病之间有明显的相关性,提示TBX20基因在人类先天性心脏病的发生过程中可能起着重要作用.但目前关于TBX20基因与人类先天性心脏病相关性的研究甚少.该文综述了TBX20基因的结构、表达、在心脏发育中的功能与途径以及在人类先天性心脏病发生中的最新研究进展.     

Tbx2基因调控胚胎心脏发育的研究进展

胚胎心脏的正常发育有赖于各相关基因的精确表达,涉及复杂的基因调控模式,其中任一环节出现偏差都会导致心脏畸形的发生.不同物种的Tbx2基因表达最终都局限在非腔室心肌区域的房室管,这提示Tbx2基因在心脏发育中时空表达的一致性和进化过程的高度保守性.Tbx2作为T-box转录因子家族的成员之一,主要参与心脏流出道和房室管的发生,通过调节下游目的基因的转录水平,从而引起一系列的调节通路变化.目前越来越多的研究表明,Tbx2表达水平或调控异常导致了不同模式动物心脏畸形的发生.临床报道也证实TBX2所在片段的微缺失/重复及其非编码区遗传变异与人类先天性心脏病的发生密切相关.该文综述了Tbx2在胚胎心脏发育中的功能、可能的调控机制及与先天性心脏病的关系.     

基因表达谱芯片筛选室间隔缺损胎儿心肌组织差异表达基因

目的 利用基因芯片技术观察室间隔缺损(VSD)胎儿心肌组织基因谱表达的变化,对其可能的分子机制进行初步分析.方法 病例组为孕中期VSD胎儿,对照组为同胎龄无心脏畸形的难免流产的胎儿,取胎儿心室心肌组织,提取其总RNA,采用安捷伦4×44k人全基因组表达谱芯片观察其心肌组织基因表达谱的变化,对基因芯片数据进行处理和生物信息学分析,差异基因信号通路分析,并用实时PCR方法验证芯片结果.结果 芯片筛选发现VSD胎儿心肌组织与正常胎儿心肌组织差异表达基因 1 490 个,表达差异2倍、3倍、4倍以上的基因数分别为1 314个、157个、19个;信号通路分析差异基因得到18个具有统计学意义的信号通路,其中包括与心脏发育密切相关的信号通路,如:Notch、PI3K/AKT、MAPK信号通路;随机挑选表达差异的5个基因进行验证,结果表明定量PCR检查结果与芯片筛选结果基本相符.结论 VSD胎儿心肌组织与正常胎儿心肌组织差异表达基因与心脏发育密切相关的信号通路(Notch、PI3K/AKT、MAPK信号通路)有关,这为先天性心脏病发生机制的研究奠定了良好的基础.     

Allergic factors associated with the development of asthma and the influence of cetirizine in a double-blind, randomised, placebo-controlled trial: First results of ETA®

There is a common progression known as the allergic march from atopic dermatitis to allergic asthma. Cetirizine has several antiallergic properties that suggest a potential effect on the development of airway inflammation and asthma in infants with atopic dermatitis. Methods. Over a two year period, 817 infants aged one to two years who suffered from atopic dermatitis and with a history of atopic disease in a parent or sibling were included in the ETAC^® (Early Treatment of the Atopic Child) trial, a multi-country, double-blind, randomised, placebo-controlled trial. The infants were treated for 18 months with either cetirizine (0.25mg/ kg b.i.d.) or placebo. The number of infants who developed asthma was compared between the two groups. Clinical and biological assessments including analysis of total and specific IgE antibodies were performed. Results. In the placebo group, the relative risk (RR) for developing asthma was elevated in patients with a raised level of total IgE (≥ 30 kU/I) or specific IgE (≥ 0.35 kUA/I) for grass pollen, house dust mite or cat dander (RR between 1.4 and 1.7). Compared to placebo, cetirizine significantly reduced the incidence of asthma for patients sensitised to grass pollen (RR = 0.5) or to house dust mite (RR = 0.6). However, in the population that included all infants with normal and elevated total or specific IgE (intention-to-treat - ITT), there was no difference between the numbers of infants developing asthma while receiving cetirizine or placebo. The adverse events profile was similar in the two treatment groups. Discussion. Raised total IgE level and raised specific IgE levels to grass pollen, house dust mite or cat dander were predictive of subsequent asthma. Cetirizine halved the number of patients developing asthma in the subgroups sensitised to grass pollen or house dust mite (i.e. 20% of the study population). In view of the proven safety of the drug, we propose this treatment as a primary pharmacological intervention strategy to prevent the development of asthma in specifically sensitised infants with atopic dermatitis.     

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孤独症谱系障碍(autistic-spectrum disorders,ASDs)近年来患病率逐年攀升至1%左右,其症状往往伴随终生,成为严重威胁儿童健康和发展的神经发育性疾患;注意缺陷多动障碍(attention deficit hyperactivity disorder,ADHD)是儿童期最常见的精神障碍,国内报道患病率为4.13%～5.83%,其症状可延续至青少年期,甚至到成年期[1]。这两类精神障碍在成年期的临床表现、共患病、治疗策略和预后与儿童期有哪些不同呢?本文通过回顾相     

EXCITING NEW TREATMENT APPROACHES FOR PATHYPHYSIOLOGIC MECHANISMS OF SICKLE CELL DISEASE

During the past several decades, our understanding of the complex pathophysiology of vasoocclusion associated with sickle cell disease has improved greatly. Interaction of genes, hemoglobin molecules, red cell membrane and metabolic changes, cell-cell interactions and cell-plasma interactions, red cell adhesion to vascular endothelium, activation of coagulation, and vascular reactivity play a role in vaso occlusion. Penicillin prophylaxis of pneumococcal infections and appropriate use of blood transfusions and other supportive measures improved survival of sickle cell patients. Hydroxyurea made a major impact on sickle cell therapy when it was shown to decrease acute painful episodes, acute chest syndrome, and the need for blood transfusion in adults. Significant experience in the use of hydroxyurea has been accumulated in older children. The benefits and risks of hydroxyurea for younger children and long-term risks in all patients will be evaluated in future investigations. Other promising therapies include butyrate compounds, clotrimazole, magnesium supplementation, poloxamer 188, antiadhesion agents, anticoagulant approaches, and nitric oxide. Hemopoietic transplantation remains the only curative therapy. However, several transgenic mouse models are available for studies of gene therapy or other treatment approaches on biochemical, cellular, and pathologic effects of mutant genes.     

Infiltrations of Epstein-Barr virus-carrying cells in granular lymphocyte-proliferative disorders corresponding to chronic active Epstein-Barr virus infection

A 21-year-old man with granular lymphocyte-proliferative disorders (GLPD) associated with chronic active Epstein-Barr virus (EBV) infection is described. Chromosomal analyses revealed several clonal abnormalities and two of them were mainly repetitious. High copy numbers of monoclonal EBV genome were also detected in the proliferative large granular lymphocytes (LGLs), indicating the monoclonal expansion of EBV-infected LGLs. The patient had an indolent course for several years, and there was no evidence of infiltrations of his bone marrow until the end stage. At autopsy, microscopic studies revealed marked infiltrations of LGL in the liver and spleen, and the infiltrating cells were NK-cell immunophenotype. The infiltrated LGLs showed latency I.     

LUTEINIZING HORMONE RECEPTOR MUTATIONS IN DISORDERS OF SEXUAL DEVELOPMENT AND CANCER

Human male sexual development is regulated by chorionic gonadotropin (CG) and luteinizing hormone (LH). Aberrant sexual development caused by both activating and inactivating mutations of the human luteinizing hormone receptor (LHR) have been described. All known activating mutations of the LHR are missense mutations caused by single base substitution. The most common activating mutation is the replacement of Asp-578 by Gly due to the substitution of A by G at nucleotide position 1733. All activating mutations are present in exon 11 which encodes the transmembrane domain of the receptor. Constitutive activity of the LHR causes LH releasing hormone-independent precocious puberty in boys and the autosomal dominant disorder familial male-limited precocious puberty (FMPP). Both germline and somatic activating mutations of the LHR have been found in patients with testicular tumors. Activating mutations have no effect on females. The molecular genetics of the inactivating mutations of the LHR are more variable and include single base substitution, partial gene deletion, and insertion. These mutations are not localized and are present in both the extracellular and transmembrane domain of the receptor. Inactivation of the LHR gives rise to the autosomal recessive disorder Leydig cell hypoplasia (LCH) and male hypogonadism or male pseudohermaphroditism. Severity of the clinical phenotype in LCH patients correlates with the amount of residual activity of the mutated receptor. Females are less affected by inactivating mutation of the LHR. Symptoms caused by homozygous inactivating mutation of the LHR include polycystic ovaries and primary amenorrhea.     

Resurgence of measles in Singapore: profile of hospital cases

OBJECTIVE: To ascertain the profile of cases of measles seen at a general hospital during a recent outbreak that occurred despite a measles vaccination program. METHODOLOGY: A retrospective study from January 1991 to March 1998. All patients with measles (ICD code 055. 9) seen at the emergency unit or as inpatients were included. RESULTS: There were 87 cases identified. The diagnosis was clinical in all and proven serologically in 71%. Eighty-five per cent of the cases occurred between January 1997 and March 1998. There was a bi-modal age distribution with peaks in the very young (相似文献   

Personality profiles and heart rate variability (vagal tone) in children with recurrent abdominal pain

The aim of the study was to explore psychological factors and autonomic activity in children with recurrent abdominal pain and to compare them with those in a control group of healthy children. The Personality Inventory for Children was used for assessment of developmental, emotional and psychosocial factors in 25 children with recurrent abdominal pain (age, 7-15 y). Parasympathetic and sympathetic functions in these children and in 23 healthy control subjects (age, 7-13 y) were also investigated, non-invasively using a computerized polygraph. Vagal tone (parasympathetic function) was indexed by calculation of respiratory sinus arrhythmia in beats/min. Skin conductance (sympathetic function) was recorded by the constant current method. On the Personality Inventory for Children, 16 patients had high scores on somatic concern. Several patients had scores in the clinical range for depression, withdrawal and anxiety, but the mean scores for these personality profile scales were well within the normal range of healthy children. Interestingly, there was a spike on the L (Lie)-scale for most of the patients and 15 patients had scores above or close to the clinical cut-off value. As compared with the scores in healthy children, vagal tone and sympathetic tone were normal. Conclusion: Many children with recurrent abdominal pain have scores in the clinical range for depression, withdrawal, anxiety and L-scale indicating coping problems, denial and a trend towards somatic concern that may contribute to the evolution of abdominal pain. Autonomic nerve activity was not disturbed in these children.     

Overcoming surfactant inhibition with polymers

Inhibition of the function of pulmonary surfactant in the alveolar space is an important element of the pathophysiology of many lung diseases, including meconium aspiration syndrome, pneumonia and acute respiratory distress syndrome. The known mechanisms by which surfactant dysfunction occurs are (a) competitive inhibition of phospholipid entry into the surface monolayer (e.g. by plasma proteins), and (b) infiltration and destabilization of the surface film by extraneous lipids (e.g. meconium-derived free fatty acids). Recent data suggest that addition of non-ionic polymers such as dextran and polyethylene glycol to surfactant mixtures may significantly improve resistance to inhibition. Polymers have been found to neutralize the effects of several different inhibitors, and can produce near-complete restoration of surfactant function. The anti-inhibitory properties of polymers, and their possible role as an adjunct to surfactant therapy, deserve further exploration.     

Understanding infant formula

The World Health organisation recommends breast feeding infants for the first six months of life. When this breast feeding does not occur either through parental choice or medical need, infant formulas will be required. There is a bewildering array of formulas on the UK market for many different requirements. When faced with an unsettled infant many parents (and healthcare professionals) will experiment with the infant formula available and then attend the paediatric clinic looking for help and advice. It is therefore essential that paediatricians understand what milks are available and what the key differences between different products are. This review attempts to provide a simple guide through many of the formulations currently available in the UK; and offers advice for the dietary management of the child with extra calorie requirements, infants with cow's milk protein allergy, gastro oesophageal reflux disease, apparent unresolved hunger and infantile colic. Whatever the underlying condition, there is likely to be an infant formula that is suitable in this generation of ever expanding formulations.