核电站事故的公众防护行动

随着核能发展不断推进,居住在核电站周围的公众数量越来越多,但是他们普遍缺乏对核辐射的基础知识,对核事故的防护行动也知之甚少。而及时、正确的防护行动可以将核电站事故对公众的健康危害降到最低。本文介绍了核电站事故后,公众的防护行动：隐蔽、体表污染去污、撤离、服用稳定性碘、食品和饮用水控制、个人防护措施、宠物照料、心理援助等,以指导公众在事故后开展正确的自救与互救,提高公众对核电站事故的应急响应能力。     

卡维地洛对高血压大鼠主动脉的保护作用

目的 :研究卡维地洛对核因子 κB(NF κB)、单核细胞趋化蛋白 1(MCP 1)在自发性高血压大鼠 (SHR)大血管中表达的影响 ,探讨其对血管保护的机制。方法 :18只雄性 12周龄SHR随机分为阳性组 ,卡维地洛组 ( 30mg/kg·d) ,美托洛尔组 ( 50mg/kg·d) ,灌喂 8周 ;另选同龄雄性WistarKyoto大鼠为阴性组 (n =6 )。用免疫组化法测各组主动脉NF κB、MCP 1的表达 ,ELISA法测血清MCP 1含量。结果 :与阴性组比较 ,阳性组主动脉组织中NF κB、MCP 1表达增加 (P<0 .0 1) ,且两者正相关 (r=0 .72 8,P <0 .0 1) ;血清MCP 1含量升高 1.6 4(P <0 .0 1)。 8周后 ,治疗组之间血压无明显差异 (P >0 .0 5) ,但卡维地洛更显著抑制NF -κB、MCP 1表达 (P <0 .0 5)。结论 :卡维地洛可能独立于降压外抑制NF κB的活化来调控MCP 1表达。     

非细胞体系核重构过程的超微结构研究

用电镜观察Lambda DNA与非洲爪蟾卵提取物在非细胞体系内的核重构,发现Lambda DNA首先诱导形成类染色质结构,膜泡、核孔复合体围绕这一结构组装成双层核膜,同时类染色质也随着核膜的装配,表现出从致密凝聚到呈现松散均匀分布的变化。有工作表明,在由染色质诱导的核重构过程中,或者是膜泡先与染色质结合,然后有核孔出现,或者是核孔物质先与染色质作用,膜泡通过结合核孔物质形成双层核膜。我们观察由外源DNA诱导的核重构过程,则发现膜泡与核孔复合体先分别独立地与类染色质结构相互作用,然后核孔复合体再镶嵌到双层核膜中。     

VP-16诱导细胞凋亡及其细胞核基质中热休克蛋白表达的研究

目的　研究VP 16诱导HL 6 0细胞凋亡的变化特点以及凋亡细胞及核基质中热休克蛋白 (HSP)表达的变化。　方法　琼脂糖凝胶电泳观察凋亡细胞基因组DNA断裂 ;TUNEL法观察凋亡细胞的形态学变化 ;用免疫印迹方法显示凋亡细胞核基质蛋白、细胞总蛋白中HSP表达的差异。　结果　VP 16作用HL 6 0细胞 0 5h出现早期凋亡特征。作用 4h可见明显的DNA梯状条带。与未凋亡的细胞比较 ,凋亡细胞核基质蛋白中HSP70和HSC70表达明显上调 ;VP 16作用 2、3及 4h细胞总蛋白中HSP70的表达随时间延长略显增加 ;诱导 2 2h比诱导 4h时去除VP 16后孵至 2 2h凋亡细胞总蛋白HSP70表达量增强了 3 4倍。　结论　 1 HL 6 0细胞早期凋亡形态出现在DNA梯状条带形成之前。 2 凋亡细胞核基质中HSP70、HSC70的表达明显增加 ,经 2、3及 4h作用的细胞总蛋白中HSP70表达差异不显著。这提示细胞凋亡后HSP70的活性位点主要位于核基质上。 3 VP 16作用细胞时间增长至2 2h ,HSP的保护作用可能消失     

Adrenal Medullary Nodules in Beckwith-Wiedemann Syndrome Resemble Extra-Adrenal Paraganglia

Clues to mechanisms regulating development and tumorigenesis may be provided by studies of unusual diseases. Beckwith-Wiedemann syndrome (BWS) is a rare congenital disorder apparently related to abnormal regulation of insulin-like growth factor-2 (IGF-2) production. IGF-2 mRNA has been previously localized to the chief cells of extra-adrenal paraganglia and to adult, but not fetal, adrenal medulla. Expression of IGF-2 by neuroblastomas has been hypothesized to reflect extra-adrenal paraganglionic differentiation. In the adrenals of a fetus with BWS, we have observed both increased numbers of chromaffin cells and organoid nodules resembling extra-adrenal paraganglia. Immunoreactive IGF-2 was observed in both cell types, but was also observed in chromaffin cells in the normal fetal adrenal. The findings suggest autocrine or paracrine influences of IGF-2 in regulating the number and phenotype of cells derived from sympathoadrenal precursors in the developing adrenal medulla as well as in extra-adrenal paraganglia. These results have implications for the interpretation of data from neuroblastoma studies.     

Human myeloma light chains with increased molecular weight: high frequency among lambda chains

The discovery of a human myeloma protein comprising a kappa L-chain with an increased mol. wt of 30,000) (Bouvet et. al., 1980) prompted investigations on the incidence of such heavier L-chains among other human myeloma proteins. In 105 samples examined, 34 were found to have L-chains heavier than normal (23,000-24,000), ranging from 25,000 up to 31,000, and five of lighter mol. wt (21,000-22,000). These mol. wt abnormalities were detected by electrophoresis in sodium dodecyl sulfate 10% polyacrylamide gels (SDS-PAGE) after reduction with 2-mercaptoethanol. The mol. wt of three of the heavier kappa or lambda chains was also estimated by filtration through a Sephadex G100 column and by sedimentation equilibrium. All three methods indicated a mol. wt increase of about 15-25% as compared with the usual mol. wt. The distribution of the high mol. wt chains among all L-chains examined was found to be 11 out of 62 kappa chains (17.7%) and 23 out of 43 lambda chains (53%) (P less than 0.001). A preferential association of such L-chains with H-chains producing multiple bands in SDS-PAGE (P less than 0.01) and an association between multiple L-chain and multiple H-chain band (P less than 0.05) were also observed. In contrast, no abnormal L-chain was found in immunoglobulins from normal subjects. Spontaneous degradation of the normal H-chains sometimes yielded fragments of 30,000 mol. wt. These fragments were easily distinguishable from abnormal L-chains. The nature of extra mol. wt in heavy L-chains was investigated for the presence of carbohydrate moiety. Four large and three normal size L-chains were examined for amino-sugar and sialic acid content. A small amount (one residue per molecule) of amino-sugar was detected only in two normal and two heavy L-chains, whereas sialic acid was only found in the heaviest (27,000-30,000) L-chains (Lh) and in small percentage (one or two residues per molecule). Total sugar estimation in one Lh chain indicated a proportion not exceeding three or four residues per L-chain (mol. wt 1,000) and this is insufficient to explain the 15-25% (3,600-6,000) mol. wt increase. It is therefore possible that, at least in some heavy myeloma L-chains, an additional peptide is expressed. Whatever the nature of the increase it would be of interest to elucidate whether this is a marker of malignant process or of an intermediate step of normal Ig synthesis.     

Dose to patients through nuclear medicine procedures in a department in northern Greece

Diagnostic nuclear medicine procedures in a large hospital in northern Greece during 1984–1988 have been surveyed in order to estimate the radiation burden to the patients. The mean effective dose equivalent (EDE) was found to be 1.96 mSv/examination and 2.46 mSv/patient, allowing for the fact that a number of patients underwent more than one examination. Apart from EDE, absorbed dose has been calculated for bone marrow, thyroid, gonads, kidneys and bladder. Patients undergoing multiple examinations have been used to calculate true patient dose distribution as well as patient time-weighted dose distribution. Because of the predominance of renal examinations, 8.5 fatal renal malignancies are expected per 100000 patients.     

31P and23Na nuclear magnetic resonance study on forebrain ischemia in rats with shift reagent Dy(TTHA)

³¹P and ²³Na nuclear magnetic resonance (NMR) spectroscopy was employed to study the dynamic changes in intracellular high-energy phosphates and sodium during 15min of forebrain ischemia and recirculation in in vivo rat brain. In the presence of the shift reagent Dysprosium triethylenetetramine-N,N,N,N,N,N-hexaacetic and [Dy(TTHA)], the sodium peak separated into two peaks, unshifted and shifted. During 15min of ischemia, the unshifted sodium peak decreased and the shifted sodium peak increased. With recirculation, the unshifted and the shifted sodium peaks returned to the preischemia level within 10min, but the shifted one increased during 30–60min. Intracellular high-energy phosphates and intracellular pH (pHi) decreased during 15min of ischemia and returned to the preischemia levels within 20min of recirculation. We conclude that the decrease in unshifted sodium peak during ischemia is due to the decrease in subarachnoid sodium and the cellular influx of interstitial sodium would be minimum. The increase in shifted sodium peak during ischemia is considered to be due to the dilatation of cerebral blood vessels and the increase in interstitial sodium which was transported from subarachnoid space.(Kurata M: ³¹P and ²³Na nuclear magnetic resonance study on forebrain ischemia in rats with shift reagent Dy(TTHA). J Anesth 7: 325–333, 1993)     

EB病毒LMP1在鼻咽癌细胞中通过IκBα的降解活化NF-κB

目的　阐明鼻咽癌细胞中EB病毒编码的潜伏膜蛋白 1(LMP1)活化核转录因子NF κB的机制。方法　利用强力霉素Dox诱导表达LMP1的鼻咽癌细胞株Tet on LMP1 HNE2为实验模型 ,首先应用免疫印迹方法测定Dox诱导后不同时相LMP1的表达动力学以及IκBs蛋白量及功能的改变。进而用间接免疫荧光法检测NF κB的亚细胞定位。最后采用瞬间共转染及报道基因活性分析分析NF κB的活性。结果　在鼻咽癌细胞Tet on LMP1 HNE2中 ,Dox处理 15分钟后LMP1的表达迅速升高并维持与较高水平直至 12 0分钟。LMP1的诱导性表达导致IκBα的磷酸化并降解 ,但IκBα蛋白总量无改变。继IκBα的磷酸化并降解 ,NF κB(P6 5 )自胞浆易位至胞核且活性升高。IκBα的显性负性突变子抑制NF κB(P6 5 )的核易位及报道活性。LMP1的诱导性表达并未引起IκBβ蛋白水平变化。结论　在鼻咽癌细胞Tet on LMP1 HNE2中 ,EB病毒LMP1通过IκBα的磷酸化并降解激活核转录因子NF κB的活性 ,并且 ,LMP1诱导的NF κB活性能被IκBα的显性负性突变子完全抑制。IκBβ在此信号传导途径中无改变。LMP1表达前后IκBα蛋白总量维持恒定可能是由于NF κB的活化迅速启动了IκBα的重头合成这一自身调节环路所致。