速激肽受体拮抗剂对白三烯C_4诱导豚鼠气道收缩和微血管渗漏的作用

本实验探讨了内源性速激肽是否参与白三烯Ｃ４（ＬＴＣ４）的气道效应．ＬＴＣ４（０．５μｇｋｇ－１，ｉｖ）可增高豚鼠肺内压（ＩＰＰ）和气道内依文思蓝渗出。速激肽ＮＫ－１受体拮抗剂ＣＰ－９６３４５｛（２Ｓ，３Ｓ）－顺式－２－（二苯甲基）－Ｎ－［（２－甲氧苯）－甲基］－１－杂氮双环［２．２．２］辛烷－３－胺｝１ｍｇｋｇ－１，ｉｖ，可减弱ＬＴＣ４诱导的依文思蓝渗出；ＮＫ－２受体拮抗剂ＳＲ－４８９６８｛（Ｓ）－Ｎ－甲基－Ｎ－［４－（４－乙酰氨基－４－苯基哌啶）－２－（３，４－二氯苯基）丁基］苯甲酰胺｝，１ｍｇｋｇ－１，ｉｖ，可抑制ＩＰＰ的增高．白三烯拮抗剂ＯＮＯ－１０７８（０．０３ｍｇｋｇ－１，ｉｖ）可阻断这两种反应．结果说明内源性速激肽增强ＬＴＣ４的气道作用，其中ＮＫ－１受体介导微血管渗漏，ＮＫ－２受体介导支气管收缩．     

Iridium‐mediated β‐deuteration of enones

Exposure of captodative enone systems to deuterium in the presence of Crabtree's catalyst ( 1 ) results in deuteration at the vinylic site β‐ to the ketone carbonyl, as well as at any accessible ortho‐position. β‐exchange is also observed during the reduction of ethyl cinnamate ( 3 ) catalyzed by 1 . Copyright © 2003 John Wiley & Sons, Ltd.     

家兔未成熟心肌缺血再灌注肌浆网摄钙功能的初步研究

目的 :从亚细胞水平研究未成熟心肌缺血 -再灌注损伤中肌浆网 (SarcoplasmicReticulum ,SR)摄钙功能。方法 :36只家兔随机分为 4组 ,进行离体心灌注。组Ⅰ :幼兔 ,单纯灌注 30min ;组Ⅱ :幼兔 ,停搏 6 0min ,再灌注 30min。组Ⅲ、组Ⅳ为成兔 ,处理分别同组Ⅰ、组Ⅱ ,进行对照。测定各组心功能、冠状动脉流出液血气 ,单细胞内游离钙离子浓度 ([Ca2 + ]i) ,肌浆网Ca2 + -ATPase活性 ,肌浆网45Ca2 + 摄取。结果 :缺血 -再灌注后 ,成熟与未成熟心肌均发生钙超载 (P >0 .0 5 )。未成熟心肌肌浆网Ca2 + ATPase活性 ,肌浆网45Ca2 + 摄取恢复率 ,明显高于成熟心肌 (P <0 .0 5 )。结论 :未成熟心肌缺血 -再灌注损伤钙超载机制不同于成熟心肌 ,肌浆网钙摄取功能 ,在钙超载损伤中不起主要作用。     

The depressing effect of tetracaine and ryanodine on the slow outward current correlated with that of contraction in voltage-clamped frog muscle fibres

The effects of tetracaine (10–50 M) and ryanodine (0.1–10 M) were tested on the slow outward K⁺ current (I _so) and the mechanical tension of isolated frog muscle fibres in a voltage-clamp device (double mannitol-gap) connected to a mechanoelectric transducer. In the concentration range tested, both drugs induced a simultaneous inhibition of tension and current. In all cases the effect on tension was twice that on current. The tetracaine-induced current and tension blocks were fully reversible and dose-dependent. In contrast the ryanodine effects on current and tension were not reversible and did not exhibit a dose dependence except for the delay before the onset of the response, which was shortened when the concentration was raised. Linear regression analysis of the time-dependent and dose-dependent effects of both drugs indicated a strong correlation between the decreases in tension and current. It is concluded that the slow outward current is partly under the control of the Ca²⁺ release from sarcoplasmic reticulum during contraction.     

Localization of class i histocompatibility molecule assembly by subfractionation of the early secretory pathway

Class I molecules of the major histocompatibility complex bind peptides derived from cytosolic proteins and display them on the cell surface. This function alerts cytotoxic T cells to the presence of intracellular pathogens. Class I molecule assembly requires the association of the heavy chain with β₂-microglobulin, accompanied by peptide loading via specific transporters. This study localizes where these assembly steps take place, using monoclonal antibodies recognizing class I molecules in different assembly states to analyze subcellular fractions of the early secretory pathway. The distribution of peptide-loaded class I molecules was more localized than the distribution of the total pool of class I molecules in the early secretory pathway. Loaded molecules colocalized with the peptide transporter, free heavy chains, and the chaperone calnexin in high density rough endoplasmic reticulum (RER) membranes. These data suggest that subunit assembly and peptide acquisition occur at the same intracellular site. Class I molecules also localized to less dense subfractions of the early secretory pathway, which contained comparatively less peptide-loaded molecules than the high density RER fractions, at steady state. Following a 15 °C temperature block, class I molecules accumulated in these less dense membrane fractions, indicating that these fractions represent the intermediate compartment where empty class I molecules are trapped in mutant cells. In the presence of cycloheximide, a pool of class I molecules recycling to the RER was detected, suggesting empty molecules recycle to acquire peptide.     

The late component of L-type calcium current during guinea-pig cardiac action potentials and its contribution to contraction

 L-Type Ca²⁺ current (I _Ca,L) elicited during the action potential (AP) of guinea-pig ventricular myocytes exhibits an early and a late component. The whole-cell patch-clamp technique was used to characterize the process regulating the late I _Ca,L component and to assess its contribution to excitation-contraction coupling. A stepwise decrease in repolarization rate of AP-like voltage-clamp pulses led to an exponential increase in Ca²⁺ charge carried by I _Ca,L. This saturation behaviour was significantly reduced or absent when Ba²⁺ or monovalent cations were used as charge carriers, which suggests that the late component of I _Ca,L is controlled mainly by Ca²⁺-dependent processes. Simultaneously recording I _Ca,L and zero-load shortening or the internal Ca²⁺ concentration (fura-2) revealed that Ca²⁺ carried by the late component of I _Ca,L markedly contributes to the Ca²⁺ content of the sarcoplasmic reticulum (SR). Reducing the charge transfer by late I _Ca,L during a series of AP-like conditioning clamp pulses by 48% reduced the shortening amplitude during a subsequent test stimulation by 56%. This relationship was absent during long rectangular depolarizing conditioning clamps, during which Na⁺/Ca²⁺ exchange increased its influence on SR Ca²⁺ loading. The late component of I _Ca,L developed only a minor direct influence on the simultaneous cell shortening. Thus, the main contribution of the late I _Ca,L component is to supply Ca²⁺ for SR loading. Received: 5 November 1997 / Received after revision: 12 June 1998 / Accepted: 15 June 1998     

CORRELATION OF SKIN POTENTIAL AND SKIN RESISTANCE MEASURES

Simultaneous measurements of skin potential (SP) and skin resistance (SR) obtained from 20 male and 20 female adult subjects during 2 sessions held 2 to 9 days apart were used in studying (1) the correlation of change measurements and prestimulus level in the two measures, and (2) the amount of correlation between SP and SR using both simple difference and residual change scores in which the regression of poststimulus values on initial level (prestimulus) has been controlled. Correlations within Ss and correlations among Ss showed large individual variability, correlation differences between males and females, and high correlation between SP and SR change scores. Although the law of initial value (LIV) seemed to have little applicability to the measurement of electrodermal responses, the results underscored the need to control for contamination of change measures by initial level regardless of direction.     

Cytotoxic effector cells against HLA antigens in strong linkage disequilibrium: identification of a strong,new, CML determinant

Three sets of cytotoxic effector cells were generated against the A1, B8, DR3 haplotype using haptoidentical individuals in three different families. The three sets of effector cells generated against this haplotype showed excellent reproducibility testing, strong cytotoxicity against their specific targets, low autologous kill, and segregation with the sensitizing haplotype within the family. When tested against a panel of cells bearing all combinations the A1, B8. DR3 antigens, a hierarchy of contribution of the individual HLA antigens as CML target determinants was seen. A new strong target cell determinant was identified by cytotoxicity with one of the effector cells not explicable in terms of the A1, B8, DR3 antigens or known HLA cross-reactivity. A family study demonstrated that this determinant clearly segregates with HLA. The success of this approach in defining new CML determinants may result from the generation of effector cells across a single haplotype in strong linkage disequilibrium or from the presentation of CML determinants in the context of self.     

人SR-AI转基因小鼠遗传与繁育的研究

目的探讨被转入的人SR-AI基因的整合与复制情况及其对小鼠繁育的影响.方法采用类似系祖建系的方法,对人SR-AI转基因小鼠的2、3534、3560、3638、3639五个系列进行了繁育.并用PCR和Southermblot的方法,检测五个系列小鼠尾组织的DNA样品.结果五个系列小鼠共产仔431只,PCR检出阳性小鼠178只,阳性率为41.2%.在3639系的F1、F2、F3代及纯合子转基因鼠中PCR阳性率分别为47.8%、71.3%、75%和100%.结论人SR-AI基因在子代鼠中能稳定遗传,且对生殖和发育无明显影响.