军用核设施退役作业辐射防护管理建议

目的：保证军用核设施退役作业安全，有序并有效控制人员受照剂量。方法：专题研究并咨询辐射防护专家。结果：提出了剂量控制限值和管理要求，并已被有关军用标准采用。结论：对提高军用核设施退役作业人员和环境辐射安全性有重要意义。     

大剂量甲氨蝶呤在预防儿童中枢神经系统白血病中的作用

目的：探讨大剂量甲氨蝶呤（ＨＤＭＴＸ）对预防儿童急性淋巴细胞白血病（ＡＬＬ）所致中枢神经系统白血病（ＣＮＳＬ）的作用。方法：１２例患儿ＭＴＸ剂量按３．０ｇ／ｍ２计算，总量１／３加等渗盐水３０ｍｌ于３０ｍｉｎ内静脉推注，余２／３量加入１０％葡萄糖１５００～２０００ｍｌ中２４ｈ静滴，结束后鞘内注射ＭＴＸ加地塞米松１次，２４ｈ后应用四氢叶酸钙解救，剂量为每次１２ｍｇ／ｍ２，每６ｈ肌注１次，共６～８次。结果：血清ＭＴＸ的最高浓度为（０．８７～１．２３）×１０－４ｍｏｌ／Ｌ，用药２４ｈ后有效浓度仍在（１．０～７．０）×１０－７ｍｏｌ／Ｌ范围内。脑脊液的ＭＴＸ浓度在（２．０～８．８）×１０－７ｍｏｌ／Ｌ，足以杀灭中枢内白血病细胞，除１例出现严重中毒外，其余病例不良反应均较轻。９例坚持治疗１８个月，除１例复发外，８例连续完全缓解。结论：ＨＤＭＴＸ治疗有利于减少患儿ＡＬＬ的发复，有提高长期无病生存率的作用     

卧位电子线全身照射的剂量分布

对Ｔ细胞淋巴瘤等广泛的皮肤病变患者采用仰卧和俯卧的电子线全身疗法。加速器光阑开到最大，不加限光筒。治疗时沿患者纵轴，３～４个野覆盖全长，机架对两种体位顺时针、逆时针４５°各照１次。用胶片法检测相邻野间的剂量均匀性，未见明显的剂量热点和冷点。用热释光剂量计等间隔地分布在人体模型６个不同体层上，６０个测试点结果表明全身剂量均匀性在±１０％以内。     

空气中天然放射性气溶胶的测量及其所致呼吸器官受照剂量的估算

本实验以相对半定量的全小肠嗜银染色计数嗜银细胞的方法对⁶⁰Coγ线不同剂量及不同时间全身一次性照射后小鼠全小肠嗜银细胞的变化进行了观察,发现1～7Gy照射后72小时,嗜银细胞数量随着照射剂量的增加逐渐增多,7Gy达峰值,8 Gy后则随剂量的增加呈指数减少,至160Gy仅为对照的11%.变化最显著的区域在10～30Gy.照射后不同时间的变化结果表明,8.10Gy照后1天嗜银细胞减少60%,2天开始回升,4～7天出现超常,2周时恢复正常.15、20Gy照后1夭减少显著,2天略见回升,8～5天又复减少.30Gy照后嗜银细胞呈进行性减少直至动物死亡.这一实验结果提示小肠嗜银细胞与电离辐射的量效关系有独特的规律性变化.     

Estimating impossible curves using NONMEM

1 On fitting model equations to experimental data, the situation may arise that individual subjects provide insufficient information to obtain adequate parameter estimates due to the fact that not all aspects are exhibited by all subjects or that the models are simply too complex. This may be solved by applying nonlinear mixed effect modelling to the data, which integrates the information provided by different subjects.
2 We aim to provide insight into the methodology and its use in these situations, illustrated by three examples: determination of pharmacokinetics in a rising dose design, where the lower doses provide insufficient information (due to assay limitations) to estimate terminal half-life; determination of the kinetics of the low molecular weight heparin enoxaparine (Clexane^®) using anti-Xa activity, effectively dealing with lingering low/basal activity; simultaneous estimation of the pharmacokinetics and pharmacodynamics of the low molecular weight heparin dalteparine (Fragmin^®) after subcutaneous and intravenous administration.     

Determination of threshold UV-A elicitation dose in photopatch testing

Photopatch testing, although widely used in the diagnosis of photosensitivity disorders, is not Standardized. We performed this study to determine the threshold ultraviolet tight A (UV-A) dose required to elicit photopatch test responses. 4 patients with previously positive tests were reexposed to the offending allergen, using an incremental dosage regime. Isopropyl dibenzoylmethane (Eusolex 8020), mexenone (benzophenone-10) and oxybeozone (benzophenone-3) produced positive responses at 1.0, 1.0 and 0.7 J/cm², respectively. Responses to phenothiazines were deemed phototoxic. These results demonstrate that high doses of UV-A (e.g., 10–15 J/cm²) are unnecessary, and that 5 J/cm² should become the current Standard.     

硬膜外试验剂量在老年人麻醉中的可靠性探讨

将70例硬膜外麻醉病人分为60岁以下组和60岁以上组(老年组)。按自身交叉随机设计原则在硬膜外或静脉内注射2%利多卡因3ml(含肾上腺素15μg)。静注后老年组和非老年组心率分别增快18.8±8.60beat/min 和29.3±16.64beat/min(P<0.01);分别有11例和32例病人有自觉症状(P<0.01)。单独据心率或症状判断试验液是否误注血管,准确性分别为老年组88.5%或84.25,非老年组94.2%或95.7%;联合判断其准确率分别为90.0%和95.7%。提示硬膜外试验剂量在老年人麻醉中的可靠性较差。     

Prognostic factors of inoperable localized lung cancer treated by high dose radiotherapy

A retrospective study was made of the results of high dose radiotherapy (≥50 Gy) given to 171 patients with inoperable, intrathoracic non small cell lung cancer from January 1971–April 1973. Local control was dependent on the total tumor dose: after one year local control was 63% for patients treated with >65 Gy, the two year local control was 35%. If treated with <65 Gy the one year local control was ≤40%. Tumor doses correlated with the size of the booster field. If the size of the booster field was <100 cm², the one year local control was 72%; the two year local control was 44%. Local control was also influenced by the performance status, by the localization of the primary tumor in the left upper lobe and in the periphery of the lung. Local control for tumors in the left upper lobe and in the periphery of the lung was about 70% after one year, and about 40% after two years. The one and two years survival results were correlated with the factors influencing local control. The dose factor, the localization factors and the performance influenced local control independently. Tumors localized in the left upper lobe did metastasize less than tumors in the lower lobe, or in a combination of the two. This was not true for the right upper lobe. No correlation between the TNM system, pathology and the prognosis were found.     

Pharmacokinetics and relative bioavailability of heptabarbital and heptabarbital sodium after oral administration to man

Summary A method has been developed for the quantitative determination of heptabarbital [5-(1-cyclohepten-1-yl)-5-ethylbarbituric acid] in human plasma after administration of single therapeutic doses of the drug. It involves a single extraction step followed by gas chromatography with alkali flame ionization detection, and the results were linear in the concentration range 0.125 – 5.0 µg/ml plasma. The pharmacokinetics and relative bioavailability of heptabarbital and heptabarbital sodium were studied in a crossover design in 7 healthy volunteers after oral administration of 20 tablets containing 200 mg heptabarbital and hard gelatine capsules containing an equivalent amount of its sodium salt. Heptabarbital concentrations in plasma were determined at regular intervals. The absorption of heptabarbital from the tablets was quite slow and peak level times varied from 1.5 to 4 h. The sodium salt was absorbed more rapidly and peak concentrations occurred between 1/3 and 2 h. In all cases the elimination of heptabarbital could be described by a single first-order process with an average half-life of 7.6 h (range 6.1 – 11.2 h). The half-life of the drug in each individual was about the same in the two trials. The relative bioavailability in each volunteer was estimated by comparing the areas under the plasma concentration curves. The sodium salt had an average bioavailability of 83% relative to the free acid. In some volunteers urinary excretion of unchanged heptabarbital was measured; cumulative excretion amounted to 0.16 – 0.30% of the administered dose. Four volunteers received one tablet each night for eight or ten days, but no accumulation was found. In three volunteers the half-life of the drug prior to and after these experiments did not change, whereas in the other volunteer the half-life decreased from 7.1 to 4.6 h. The possibility of enzyme induction should be considered when heptabarbital is taken regularly. It was concluded that heptabarbital was a suitable drug for the treatment of insomnia, since its half-life was rather short. Heptabarbital sodium may be used for induction of sleep, whereas Medomin^® tablets, i.e. heptabarbital free acid, may be prescribed when the maintenance of sleep is the primary reason for treatment with a hypnotic drug.