螺旋CT双期增强扫描与病灶延迟期扫描在肝癌诊断中的应用

目的：研究螺旋CT动脉期、门脉期及病灶延迟期扫描在肝癌诊断中的应用，以进一步选择理想的扫描时期和方案。方法：对48例肝细胞性肝癌患者行平扫及增强扫描，造影剂注射速率为3ml/s，然后开始动脉期、门脉期及病灶延迟期扫描。统计各期的病灶检出数，观察病灶在不同时期的特征。结果：动脉期、门脉期及病灶延迟期的病灶检出率分别为91.9％、76.9％、78.8％，动脉期和门脉期、病灶延迟期之间均有显著差异，而门脉期和病灶延迟期之间无差异。结论：在肝癌的检出方面动脉期价值最大，而门脉期和延迟期之间无差异。双期扫描（动脉期加门脉期）可作为肝癌CT诊断的常规技术，对不典型病例，病灶延迟期很有必要，有助于病灶的定性。     

Ames试验检测三硝基甲苯及其还原代谢产物的诱变性

应用Ａｍｅｓ试验检测系统观察了三硝基甲苯及其还原代谢产物４－羟氨基－２，６－二硝基甲苯（４－ＨＡ），４－氨基－２，６－二硝基甲苯（４－Ａ），２－氨基－４，６－二硝基甲苯（２－Ａ）和２，４－二氨基－６－硝基甲苯（２，４－ＤＡ）的诱变活性，实验结果显示，三硝基甲苯及其代谢产物具有明显的致突变作用，４－Ａ的直接诱变活性最强，而且移码型诱变性更为显著，在微粒体酶系统的参与下，ＴＮＴ的诱变活性增强，其代谢产     

Human interleukin 4 regulates the phenotype of lymphocytes generated during mixed lymphocyte culture and inhibits the IL-2-induced development of LAK function in normal and leukaemic cells

This study examined the immunoregulatory role of recombinant interleukin 4 (IL-4), also known as B-cell stimulating factor 1, on the generation of cytotoxic effector cells from normal and leukaemic human blood mononuclear cells. When tested on cells from normal individuals, the addition of IL-4 to mixed lymphocyte cultures led to a dose-dependent proliferation of T-helper cells (CD3, 4 positive) with a concomitant decrease in phenotypic and functional cytotoxic T cells and natural killer (NK) cells. IL-4 also inhibited the interleukin-2 (IL-2)-induced generation of lymphokine-activated killer (LAK) activity when added at the beginning of mixed lymphocyte culture. When tested on mature leukaemic NK cells, IL-4 also inhibited the ability of IL-2 to induce LAK function using a short-term culture system. These results show that IL-4 acts on both normal and leukaemic cells and suggests that it acts at more than one level during the development of LAK function.     

Stereoselectivity of actions of the calcium sensitizer [+]-EMD 60263 and its enantiomer [-]-EMD 60264

The thiadiazinone derivative [+]-EMD 60263 ((+)-5-(1-(α-ethylimino-3,4-dimethoxybenzyl)-1,2,3,4- tetrahydroquinoline-6-yl)-6-methyl-3,6-dihydro-2H-1,3,4 -thiadiazine-2-on) is a Ca²⁺-sensitizing agent with only minor phosphodiesterase inhibitory activity. Our aim was to characterize the inotropic and electrophysiological effects of [+]-EMD 60263 and its enantiomer [-]-EMD 60264 in several cardiac muscle preparations. The Ca²⁺-sensitizing activity resided in the [+]-enantiomer only. [+]-EMD 60263 (3 μM) shifted the EC₅₀ of Ca²⁺ for contractile activation of skinned fibers of pig heart from 2.41 μM to 0.73 μM, whereas [-]-EMD 60264 (30 μM) was ineffective. In Langendorff-perfused guinea pig hearts, [+]-EMD 60263 and [-]-EMD 60264 induced concentration-dependent positive and negative inotropic effects, respectively; both enantiomers reduced spontaneous heart rate but did not influence perfusion pressure. The maximum increase in force of human atrial trabeculae was 35 % of pre-drug control with [+]-EMD 60263 in comparison to 113 % with forskolin. In guinea-pig papillary muscles, [+]-EMD 60263 and [-]-EMD 60264 had opposite inotropic responses, however, both agents similarly prolonged action potential duration. Both enantiomers concentration-dependently blocked the rapidly activating component I_Kr of the delayed rectifier in guinea-pig myocytes. The block saturated at potentials positive to +30 mV, closely resembling the effects of the antiarrhythmic agent E-4031 which had been originally used to define I_Kr. It is concluded, that the positive inotropic action of [+]-EMD 60263 can be explained by prevalence of the Ca²⁺-sensitizing effect. The accompanying prolongation in action potential duration is caused by block of the I_Kr component of the delayed rectifier. While the inotropic effects are stereoselective, most of the electrophysiological actions are clearly independent of sterical configuration. The combination of Ca²⁺-sensitizing with class-III antiarrhythmic action may provide an interesting pharmacological profile of potential therapeutic use. Received: 7 January 1997 / Accepted: 25 February 1997     

石家庄地区汉族人群DIS80(pMCT118)位点VNTR基因频率分布调查

本文采用ＰＣＲ技术对石家庄地区２１６名无关个体ＤＩＳ８０（ｐＭＣＴ１１８）位点扩增片段长度多态性的等位基因频率进行调查。ＰＣＲ扩增产物采用聚丙烯酰胺凝胶电泳分型及溴化乙锭染色，共检出７０种基因型，２５个等位基因，其中以１８、２４、３０三个等位基因频率最高。将本文结果与日本人群在ＤＩＳ８０（ｐＭＣＴ１１８）位点多态性结果进行比较，石家庄地区汉族人群ＤＩＳ８０（ｐＭＣＴ１１８）位点基因频率分布符合ＨａｒｄｙＷｅｉｎｂｅｒｇ平衡定律，该位点非父排除率为０．７１，个体识别率为０．９，杂合度为０．８５。     

慢性低氧大鼠肺动脉内皮素mRNA的表达及定位

目的：探讨慢性低氧大鼠肺动脉内皮素－1基因表达及分布。方法：采用生物素标记cRNA探针，对Wistar大鼠肺动脉进行原位杂交。结果：低氧1周组及低氧2周组大鼠大部分肺动脉内皮细胞ET－1mRNA表达呈阳性信号，而对照组大鼠仅极少数阳性信号（P＜0．01）；低氧1周组大鼠部分显示强阳性信号。低氧1周组及低氧2周组大鼠部分肺动脉平滑肌细胞呈现ET-1mRNA表达阳性信号，而对照组大鼠则无阳性信号表达（P＜0．01及0．05）。结论：慢性低氧对大鼠肺动脉ET－1分泌的影响是在基因转录水平进行，且主要细胞定位在肺动脉内皮细胞，此外还包括肺动脉平滑肌细胞。     

Investigation of Role of Nitric Oxide in Protection from Bordetella pertussis Respiratory Challenge

The mechanism whereby whole-cell pertussis vaccines (WCV) confer protection against Bordetella pertussis is still not fully understood. We have previously reported that macrophage activation produced by vaccination with WCV is associated with induction of NO synthesis by macrophages in response to in vitro stimulation with B. pertussis antigens. To determine whether NO production is an effector of protection or simply a marker of activation, the susceptibility of inducible nitric oxide synthase (type II, iNOS) knockout mice to infection with B. pertussis was examined. We showed that iNOS knockout mice were more susceptible to B. pertussis respiratory challenge than wild-type mice. iNOS-deficient mice also developed a less effective protective response than wild-type mice after the same immunization with WCV. This suggests that NO plays an important role in effecting protection against B. pertussis challenge.     

Spermidine synthase of Escherichia coli: localization of the speE gene.

We have obtained Escherichia coli mutants lacking spermidine synthase (putrescine aminopropyltransferase) and have found that the mutated gene (speE) is located immediately upstream from the gene coding for S-adenosylmethionine decarboxylase (speD); these genes are located at 2.7 minutes on the E. coli chromosome. Both genes are present in a 1795-base-pair fragment of E. coli DNA that was cloned into pBR322. Deletion of 105 bases upstream of speE caused a coordinate loss of both activities, indicating that speE and speD constitute a single operon. speE and speD have also been cloned separately in a high-expression vector; strains carrying these plasmids overproduce the respective enzymes.     

Effect of gradual rise in plasma calcium concentration on the impairment of atrioventricular nodal conduction due to verapamil

The possible reversal by calcium of the inhibitory action of verapamil on the atrioventricular (AV) node was investigated in anesthetized, atropinized dogs, with cardiac pacing. The His bundle potentials were recorded by endocavitory electrode and the AV node effective refractory period measured by the extrastimulus method. Calcium infusion was effective against the impairment of AV nodal conduction induced by verapamil, provided it remained moderate: the gradual rise in the plasma calcium concentration counteracted the effects of an infusion of verapamil on conduction time and effective refractory period in the AV node, as long as it did not exceed 5 mmol/L. However, beyond this level, calcium appeared less and less capable of reversing the effects of verapamil. Thus, the protective action of calcium had a bell-shaped dose-response curve, with the optimum at 5 mmol/L. This biphasic influence is consistent with the opposite opinions previously given concerning the antagonism between calcium and calcium blockers, depending on whether hypercalcemia brought into play was mild or major. In any case, the prominent role played by calcium in the slow inward current in the AV node accounts for the antagonism, observed in vivo, between calcium and verapamil. The pacemaker activity of the sinoatrial (SA) node was less influenced by both calcium blocker and calcium.