Transport of methylmercury—cysteine conjugate by system L—tpye amino acid transporters and its transportermediated toxicity

Methylmercury(MeHg) is widely known for its potent neurotoxicity and the causal substance of Minamata disease.Since the conjugates of MeHg with thiol compounds are easily formed in vivo,the metabolism and transport of glutathione,cysteine and their derivatives are important determinants of tissue distribution and elimination of MeHg.It has been proposed that the amino acid transport system L,which transports large neutral amino acids,is one of the major routes for MeHg mobilization.We have identified two isoforms of system L amino acid transporters:L-type amino acid transkporter-1(LAT1) and LAT2 and found that they transport MeHg as a cysteine-conjugate (MeHg-Cys).We have further found that a classical system L inhibitor BCH[2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid] rescued T24 human bladder carcinoma cells expressing LAT1 form the toxicity of MeHg-Cysl.We concluded that the cytotoxicity of MeHg is mediated by system L transporters.The fact that BCH reduced the toxicity of MeHg-Cys suggests that the high-affinity inhibitors of system L transporters could be a new rationable to avoid MeHg-toxicity.     

慢性便秘结肠运输试验临床应用分析(附31例报告)

目的：通过对31例慢性便秘（CC）结肠运输试验的临床观察，分析结肠运输障碍原因，为临床治疗慢性便秘提供客观理论依据。方法：自1998年8月起，对31例CC患者行结肠运输试验并分别试行治疗。结果：5例结肠运输功能正常，9例结肠运输相对延缓，7例结肠运输绝对延缓，10例结肠运输正常但直，乙结肠运输时间延长，据此分别进行不同的治疗，取得较好的治疗效果。结论：结肠运输试验对确定慢性便秘病因和治疗有较好的临床应用价值。     

李明博:从穷孩子到韩国总统

<正>一个靠深夜捡垃圾完成学业的贫寒少年一个因不满军政府统治领导学生运动的激进分子一个曾执掌跨国集团的风云人物韩国总统李明博的成功绝非简单的神话出身寒微贫穷成为一生财富1941年,李明博出生于日本大阪。4岁时,日本战败,李明博随父母回到祖国,然而,不幸的是运输财     

新疆独山子地区体检职工血型分布调查分析

独山子地区为克拉玛依市一较远的行政区,距离克拉玛依市165 km,为一大型石油化工基地,靠克拉玛依市中心血站供血.除交通不便外,还要牵涉冷链运输、质保等问题.为了适应本地区1 000万吨大炼油和120万吨大乙烯的发展,保证医院临床合理供血,建立稀有血型档案.为此,笔者对2003年1月至2006年12月11 216例体检职工ABO、RH血型分布调查结果进行分析,报道如下.     

新生儿复苏及窒息的预防护理

新生儿窒息是指胎儿因缺氧发生宫内窘迫或娩出过程中引起呼吸、循环障碍，致胎儿娩出后1min，仅有心跳而无呼吸或未建立规律呼吸的缺氧状态，是产前或产程中窒息在出生后的表现和继续，即各种原因使母胎间血氧运输及交换障碍、母体血液含氧量不足和胎儿自身因素等，导致胎儿体内严重缺氧、代谢性混合性酸中毒、中枢神经和呼吸循环等系统受到抑制的病理状态，     

结肠慢运输型便秘的诊断及治疗探讨

便秘是常见的消化道疾病，可分为慢运输型便秘和出口梗阻型便秘。为探讨结肠慢运输型便秘的诊断与治疗，作对2003年9月至2004年9月收治的慢运输型便秘13例作一分析，报告如下。     

水甘油通道3介导的甘油运输与皮肤功能

水甘油通道3(AQP3)是一种即可以运输水分子又可以运输甘油等小分子物质的双功能水通道。皮肤角质细胞AQP3介导的甘油运输对于皮肤功能具有十分重要的意义,它的功能缺陷可导致皮肤干燥、弹性下降和屏障作用减弱等皮肤损伤,而过表达则增加了皮肤癌的危险。AQP3在皮肤功能方面的多重作用使其成为皮肤相关疾病治疗和护肤产品开发等的潜在靶点。本文就AQP3的特征、功能、应用及研究展望进行综述。     

Factors influencing ambulance use in patients with ST-elevation myocardial infarction in Beijing, China

Background Emergency medical service plays a key role in the early recognition and treatment of ST-elevation myocardial infarction （STEMI）, but studies indicate that the patients experiencing STEMI symptoms often fail to call an ambulance as recommended. This study aimed to examine the current ambulance transport frequency and ascertain predictors and reasons for not choosing ambulance transportation by the patients with STEMI in Beijing. Methods A prospective, cross-sectional survey was conducted from January 1,2006 through until June 30, 2007 in two tertiary hospitals in Beijing and included consecutive patients with STEMI admitted within 24 hours of onset of symptoms. Data were collected by structured interviews and medical records review. Results Of the 572 patients, only 172 （30.1%） used an ambulance, and the remaining 400 （69.9%） presented by self-transport. Multivariate analysis showed that age 〈65 years （OR： 1.220; 95% CI： 1.001-2.043）, lower education level （OR： 1.582; 95% CI： 1.003-2.512）, presence of pre-infarction angina （OR： 1.595; 95% CI： 1.086-2.347）, and attribution of symptoms to non-cardiac origin （OR： 1.519; 95% CI： 1.011-2.284） were independent predictors for not using an ambulance. However, history of coronary artery disease （CAD）, dyspnea, perceiving symptoms to be serious, and knowing the meaning of cardiopulmonary resuscitation appeared to be independent predictors of ambulance use. The main reasons for not using an ambulance were convenience and quickness of self-transport and the decreased severity of symptoms. Conclusions A large proportion of patients in Beijing do not call for an ambulance after onset of STEMI symptoms. Several factors including demographics, previous CAD, symptoms and cognitive factors of patients are associated with the ambulance use. The public should be educated that an ambulance is not merely a transportation modality and that it also provides rapid diagnosis and treatment.     

我国二连口岸动物鼠疫稳定存在对运输安全的威胁

二连口岸既是鼠疫历史疫源地,又是现行疫区。近年来监测显示,该地区的鼠间疫情异常活跃。二连口岸是连接欧亚大陆的重要陆路通道,北京-乌兰巴托-莫斯科国际联运的必经之地,对蒙古国惟一的铁路通道,又是我国"三横九纵"国道干线二连-广州(以下简称"二广线")的一个起点,也是对蒙古国的重要公路口岸。年过货量近千万吨,出入境人数百万人。作为连接欧亚大陆的重要陆路通道,新时期,如何做好鼠疫防治工作,确保运输安全就显得格外重要。为此,笔者就二连口岸的鼠疫防治工作提出了一些对策。     

P2Y13受体在神经系统的研究进展

从靶细胞分泌的信号分子(如神经营养素)可激活轴突末梢相应受体(如Trks)形成配体-受体混合物在细胞内吞作用下进入内体,这种胞内吞细胞器可从轴突逆行转运至胞体,具有信号转运功能的这种细胞器称为信号内体[1]。信号内体的假设是建立在轴突终端观察到NGF结合并激活TrkA受体形成信号蛋白复合物的现象[2]。伴随受体介导的内吞作用,NGF激活的TrkA信号复合物被分类至内体亚群形成信号内体。信号内体参与调节与分类细胞信号,并在轴浆逆