太钢1998～2002年放射工作人员个人剂量监测分析

目的为进一步调查太钢放射工作人员外照射剂量大小，以评价太钢近几年来放射管理和放射防护效果，降低放射危害，保护放射工作人员身体健康。方法根据GB5294-85《放射工作人员个人剂量监测方法》将1998-2002年在太钢从事放射的工作人员分为4组：医用X射线、工业X射线、工业γ射线和医用同位素组，进行外照射个人剂量监测，并计算1998-2002年各年度平均年剂量当量。每年监测4个周期，每个周期为3个月，并对监测结果进行分析。结果①5个年度平均年剂量当量为1．46mSv，1998年最高，从2000年起有逐渐下降的趋势；并且除2002年与2000、2001年比较，U检验差异无统计学意义外，其余各年度之间比较，差异均有统计学意义（P〈0．01）；②1998-2002年各工种之间年个人剂量当量监测结果，以工业γ射线组均值最低，医用X射线组最高。U检验，工业γ射线组与其他3个组比较，差异有统计学意义（P〈0．01），医用X射线组与工业X射线组比较，差异亦有统计学意义；③1998-2002年各年度年个人有效剂量频数分组分布，〈1mSv／a组占受检总数的27.11％，〉5mSv／a的占0．31％，〈5mSv／a的占99．69％。经χ^2检验，各年度之间比较，差异有统计学意义（χ^2=377．33，P〈0．01）；④各工种个人剂量当量分组频数分布情况：〈1mSv／a占受检总数的26．49％，1-2mSv／a组占59．89％．2-3mSv／a占10．52％，〈5mSv／a的占99．69％，〉5mSv／a仅3例，为医用X线组。各工种之间比较，χ^2检验有统计学意义（χ^2=1030．79，P〈0．001）。结论1998-2002年平均剂量当量远低于国家标准，并逐年下降，说明近5年太钢加强放射工作人员的健康和防护设施管理的工作，放射工作环境是安全的。     

67Ga心肌炎症显像对小儿病毒性心肌炎的诊断价值

目的 :探讨6 7Ga心肌显像对小儿病毒性心肌炎 (VMC)诊断的临床价值。方法 :静脉注射6 7Ga 枸橼酸盐 ,48h、72h后开始显像 ,观察心脏部位放射性浓聚情况 ,并计算心 /肺 (H/L)指数 ,根据H/L指数判断心肌炎性病变的严重程度 (H/L指数 >1.2为阳性 )。结果 :78例病毒性心肌炎患儿中 ,50例阳性 (占 64% ) ,其中急性期阳性率为 84% ,恢复期阳性率为 50 % ,慢性期为 2 9% ,急性期阳性率明显高于恢复期和慢性期 (P<0 .0 5)。结论 :心肌6 7Ga放射性浓聚与心肌炎病变程度呈正相关 ,直接反映了病变心肌的炎症反应情况 ,对诊断VMC有较高的临床价值 ,并对VMC治疗、预后有指导作用     

Kinetics of acetylcholine recovery in Torpedo electromotor synapses depleted of synaptic vesicles

Isolated fragments of Torpedo electric organ perfused with choline-free Ringer and stimulated by application of up to 1500 pulses at 1 Hz lost 58% of their synaptic vesicles and 65% of their acetylcholine. The stimulated terminals showed ultrastructural changes of varying intensity which were reversed during rest. The numbers of synaptic vesicles returned to control values by 5 h and total acetylcholine reached the control levels only after 20 h incubation in medium containing excess of choline. Net synthesis of acetylcholine as well as acquisition of acetylcholine by the reformed vesicles followed first order kinetics with respect to the degree of unsaturation of the total acetylcholine pool and the vesicular compartment, respectively.A possible interpretation of these results is that the degree of depletion of the vesicular compartment may regulate the rate of net acetylcholine synthesis, and that the vesicular compartment may account for at least 80% of total acetylcholine in the terminals.     

Changes in the biochemical and biophysical parameters of cholinergic synaptic vesicles on transmitter release and during a subsequent period of rest

Synaptic vesicles were isolated on sucrose density gradients from perfused blocks of Torpedo electric organ under varying experimental conditions. Newly synthesized acetylcholine was labelled with [³H]acetate in order to distinguish synaptic vesicles which had been recycled during stimulation-induced transmitter release and, in consequence, had become smaller and denser from the larger, lighter vesicles characteristic of unstimulated tissue. After 1800 pulses at 0.1 Hz, the density of these smaller vesicles increased from a pre-stimulation value of 1.056 g.ml^?1 to 1.067 g.ml^?1, whereas their water space (measured as the space occupied by the permeant solute glycerol), decreased by 34% from 65% to 43% of vesicle volume. During a subsequent 12 h rest period, these changes were partially reversed; water space returned to 52% of control and this change was highly correlated with a decrease in vesicle density and an increase in vesicular acetylcholine. The diameter of vesicles in whole tissue sections showed corresponding changes. An additional 12 h rest period did not lead to further significant recovery, suggesting that the preparation had a limited suitability for following long term processes depending on normal energy metabolism.The results can be explained on the assumption that when vesicles reform after releasing transmitter their core has a lower osmotic pressure than that of fully loaded vesicles. Reloading is accompanied by osmotically induced rehydration.     

重组水蛭素在大鼠体内的药动学研究

目的研究重组水蛭素iv给药在大鼠体内的药动学。方法采用125-标记的放射性同位素法(RA法)、三氯醋酸沉淀结合放射性检测法(TCA-RA法)研究重组水蛭素iv给药在大鼠体内的药动学。结果大鼠iv0.5、1.0和2.0mg/kg重组水蛭素,以RA法检测,该药的消除半衰期(t1/2ke)分别为162.8、147.5和172.8min,AUC分别为264.9、429.9和1112.9(μg·min)/mL;以TCA-RA法检测,该药的t1/2ke分别为100、101和107min,AUC分别为160.7、327.7和551.3(μg·min)/mL。两种方法所得结果均证明AUC与剂量呈正相关,相关系数均大于0.99。大鼠iv重组水蛭素1.0mg/kg后用RA法和TCA-RA法测定不同组织的药物质量浓度,在各时间点以肾脏含药量显著高于其他组织,肺、胃、脾、心、肝、性腺等组织次之,脑、脂肪最少。大鼠iv重组水蛭素1.0mg/kg后,用RA法测定不同时间段内尿、粪的放射性总量,在96h内70.16%放射性从尿中回收,1.35%从粪中回收到,24h内胆汁排泄量为3.46%。结论RA法和TCA-RA法测得重组水蛭素在大鼠体内的药动学结果不同,但整体趋势一致;重组水蛭素主要由尿排泄。     

Natural and anthropogenic radioactivity levels and the associated radiation hazard in the soil of Oodalia Tea Estate in the hilly region of Fatickchari in Chittagong,Bangladesh

Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring ²³⁸U and ²³²Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg⁻¹ and 36 ± 11 to 72 ± 11 Bq kg⁻¹, respectively. The activity concentration of ⁴⁰K ranged from 201 ± 78 to 672 ± 81 Bq kg⁻¹, and the highest activity of fallout ¹³⁷Cs observed was 10 ± 1 Bq kg⁻¹. The average activity concentration observed for ²³⁸U was 39 ± 8 Bq kg⁻¹, for ²³²Th was 57 ± 11 Bq kg⁻¹, for ⁴⁰K was 384 ± 79 Bq kg⁻¹ and for ¹³⁷Cs was 5 ± 0.5 Bq kg⁻¹. The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil.     

On the calculation of activity concentrations and nuclide ratios from measurements of atmospheric radioactivity

Motivated by the need for consistent use of concepts central to the reporting of results from measurements of atmospheric radioactivity, we discuss some properties of the methods commonly used. Different expressions for decay correction of the activity concentration for parent–daughter decay pairs are presented, and it is suggested that this correction should be performed assuming parent–daughter ingrowth in the sample during the entire measurement process. We note that, as has already been suggested by others, activities rather than activity concentrations should be used when nuclide ratios are calculated. In addition, expressions that can be used to transform activity concentrations to activity ratios are presented. Finally we note that statistical uncertainties for nuclide ratios can be properly calculated using the exact solution to the problem of confidence intervals for a ratio of two jointly normally distributed variables, the so-called Fieller׳s theorem.     

医用直线加速器的感生放射性研究

医用直线加速器在治疗过程中会产生对人体有害的感生放射性,且这种危害正逐渐引起人们的重视。本文介绍了感生放射性的概念、产生机制,总结感生放射性对患者、工作人员及公众所造成的危害,探讨了感生放射性水平的影响因素,并总结减少其水平的措施。     

Absorption,distribution, metabolism and excretion of novel phosphodiesterase type 4 inhibitor ASP3258 in rats

The potent and selective phosphodiesterase 4 inhibitor ASP3258 is a novel therapeutic agent for asthma and chronic obstructive pulmonary disease (COPD). After a single oral administration to rats, ASP3258 is rapidly absorbed with a bioavailability of 106%. In situ absorption data indicated that ASP3258 is mainly absorbed in the small intestine. Tissue distribution data after oral administration of ¹⁴C‐ASP3258 showed rapid and extensive distribution to various tissues. Excluding the gastrointestinal tract, the tissues with the highest concentrations were liver, heart and plasma. Liquid chromatography‐nuclear magnetic resonance spectroscopy data revealed that O‐glucuronidation of the carboxylic acid moiety of ASP3258 (formation of an acyl glucuronide) plays a key role in metabolism. No indication was found that the acyl glucuronide reacted with proteins in plasma or tissues. When ¹⁴C‐ASP3258 was orally administered to intact rats, urinary and fecal excretion accounted for 1.3% and 100.6% of the administered radioactivity, respectively. After a single oral administration of ¹⁴C‐ASP3258 to bile‐cannulated rats, urinary and biliary excretion accounted for 0.7% and 93.8% of the administered radioactivity, respectively. These findings suggest that fecal excretion via bile plays an important role in the elimination of ASP3258‐derived radioactivity. In vitro metabolic profiles were relatively similar among the species examined, suggesting that our findings in rats may help us to understand pharmacokinetics, efficacy and safety profiles in humans and other species. Copyright © 2014 John Wiley & Sons, Ltd.     

重混凝土屏蔽质子放疗机房的感生放射性估算

目的 估算肿瘤质子治疗时重混凝土屏蔽墙中铁元素因中子活化产生的感生放射性⁵⁶Mn及其水平。方法 采用Geant4程序构建某质子治疗机房的重混凝土屏蔽墙模型,模拟245 MeV的质子束照射水模体产生的次级中子,统计屏蔽墙内放射性核素⁵⁶Mn的分布。将屏蔽墙按每10 cm厚度分层,计算前3层屏蔽墙中放射性核素⁵⁶Mn产生的周围剂量当量率。结果 在最大的束流照射条件（1.872×10¹⁰个）下,前3层屏蔽墙内的放射性核素⁵⁶Mn个数分别为3.10×10⁸、1.60×10⁸和9.33×10⁸个;对治疗室内1 m远处产生的周围剂量当量率分别为2.13×10^-3、8.82×10^-4 和9.10×10^-4 μSv/h,总的周围剂量当量率为3.92×10^-3 μSv/h。结论 在质子治疗时,距离射束中心轴越近,屏蔽墙的感生放射性越强;屏蔽墙前端中子活化铁元素产生的感生放射性最强,感生放射性随着屏蔽墙厚度增大呈指数形式减小,应主要考虑质子治疗机房屏蔽墙前端产生的感生放射性。