用稳定性同位素~(58)Fe中子活化法测定缺铁性贫血儿童膳食铁吸收率

本文报告了应用稳定性同位素~(58)Fe对三组缺铁性贫血儿童,分别摄取平衡膳、平衡膳加大豆蛋白膳和平衡膳加大豆蛋白加维生素C膳时,各组儿童膳食铁的吸收率。测定结果顺次分别为12.0±3.6％、10.7±4.7％和18.1±3.6％。后者高于前二者,差异显著。据此,作者同意国际营养性贫血咨询小组(INACG)以及大多数学者的主张,即大豆制品不利于或降低膳食铁的生物利用率(bioavailability)。本文并结合实验讨论了本法的原理、操作技术及误差控制等问题,评价了本法在类似工作中的重要意义。     

山东农村儿童膳食中人体锌吸收率的测定

目的:测定山东农村儿童代表性膳食中锌(Zn)的人体吸收率。方法:模拟山东农村典型膳食模式,采用富集的天然低丰度稳定性同位素67Zn标记ZnCl2,使用热电离质谱法(TIMS)检测膳食和粪便中总锌含量与67Zn/68Zn比值,计算锌的真吸收率;使用原子吸收分光光度计穴AAS雪测定膳食与粪便的总锌,计算锌的表观吸收率。同时测定影响锌吸收的因子膳食脂肪、蛋白、植酸、纤维素和维生素C(Vc)的含量,计算日平均摄入量,将其结果与我国儿童每日推荐膳食营养素摄入量(RNIs)进行比较。结果:锌的真吸收率为(12.94±3.32)%,锌的表观吸收率为(22.37±1.59)%,两者差异有统计学意义(P<0.05)。锌的平均日摄入量为11.16mg,占RNI的111.6%,高于推荐量。蛋白质和Vc的日摄入量分别为31.2g与13.3mg,占RNIs的56.73%和29.60%,低于推荐量。脂肪、植酸和膳食纤维的日摄入量较高。结论:在蛋白质和Vc的日摄入量较低,脂肪、植酸和膳食纤维的日摄入量较高的条件下,锌的真吸收率较低。     

188Re-Herceptin-磁性纳米微粒的体外抗肿瘤作用

目的探讨^188Re—Herceptin-磁性纳米微粒在外置磁场下对HER-2／neu癌基因高表达的SKBR-3乳腺癌细胞的靶向结合性及抗癌作用。方法采用戊二醛交联法使人源性单克隆抗体Her—ceptin与磁性纳米微粒交联，用直接标记法制备^188Re—Herceptin及^188Re—Herceptin-磁性纳米微粒，用羰基铼标记法制备^188Re-磁性纳米微粒。肿瘤细胞体外抑制实验设4个组：^188Re—Herceptin-磁性纳米微粒组、^188Re—Herceptin组、^188Re-磁性纳米微粒组和^188ReO4^-组，各组均设3．7×10^4、18．5×10^4、37×10^4、55．5×10^4、74×10^4Bq／ml5个放射性剂量级别；另设生理盐水对照组。采用四甲基偶氮唑蓝（MTT）法测定各组的抑瘤效应，计算相对抑制率，采用半数抑制放射性浓度（IC50）对各组抑瘤作用进行比较和评价。结果^188Re—Herceptin-磁性纳米微粒和^188Re—Herceptin组对SKBR-3细胞均有较强杀伤作用，且呈剂量依赖性；而^188Re-磁性纳米微粒和^188Re04组的杀伤作用较弱0188Re—Herceptin-磁性纳米微粒组的IC50（53．1×10^4Bq／L）明显低于^188Re—Herceptin组（76．1×10^4Bq／L）；^188Re一磁性纳米微粒组和^188ReO4组的IC50分别为169×10^4和175×10^4Bq／L，明显高于前2组。结论^188Re—Herceptin-磁性纳米微粒和^188Re—Herceptin均可明显抑制体外培养的SKBR-3乳腺癌细胞增殖，且前者的抑制作用较后者强。     

99Tcm直接标记αvβ3受体拮抗剂环形RGD多肽

目的探讨^99Tc^m直接标记αvβ3受体配体——含2个二硫键的精氨酸-甘氨酸-天冬氨酸（RGD）-九肽（RGD-4CK）的可行性和不同标记条件对标记率的影响。方法采用预锡化法^99Tc^m直接标记RGD-4CK，3MM色谱纸层析测定^99Tc^m-RGD-4CK的雕值，计算标记率与比活度。研究各种标记条件对^99Tc^m-RGD-4CK标记率的影响。通过高效液相色谱仪（HPLC）分析，Sep-Pak C18柱层析，进行体外稳定性实验、半胱氨酸置换实验以及血清蛋白结合实验，评价^99Tc^m-RGD-4CK的放射化学性质。结果^99Tc^m-RGD-4CK在以丙酮和V（氨水）：V（乙醇）：V（水）=1：2：5为流动相中的雕值分别为0与0．8～0．9，标记率为（97．8±0．4）％，基础标记条件下的比活度为（11．90±0．05）TBq／mmol。在以下条件下放化纯均〉95％：（1）酒石酸亚锡为150～300μg；（2）预锡化反应pH值为2．0～3．5，温度60℃，保温时间6h以上；（3）^99Tc^mO4^-活度为37～185MBq，体积在200μl内；（4）标记温度为95℃，标记时间30min.^99Tc^m-RGD-4CKHPLC的保留时间与其洗脱液的放射峰基本一致；^99Tc^m-RGD-4CK室温放置6h，放化纯仍〉95％；Sep—Pak C18柱层析测定的^99Tc^m O4^-峰仅比3MM纸层析高0．5％；标记物与300mmol／L半胱氨酸37℃保温1h，^99Tc^m O4^-峰仅增加1．88％；^99Tc^m-RGD-4CK与血清蛋白无明显结合。结论预锡化法^99Tc^m直接标记RGD-4CK方法简便、标记率高，无需分离纯化即可直接应用，还可用于制备冻干品药盒。标记产物^99Tc^m-RGD-4CK具有良好的放射化学性质。     

Use of a synthetic peptide-based elisa for the diagnosis of infectious mononucleosis and other diseases

A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma.     

某焦化厂新建同位素装置放射防护控制效果评价

目的 对某焦化厂新建同位素装置进行放射防护控制效果评价。方法 通过现场监测，按照标准对辐射源安全级别，场所辐射防护区域，工作人员接受的剂量水平进行分析评价。结果 只有一处密封辐射源仪表的安全级别属3级，其余均符合4级标准；1m外工人接受的最大剂量估算值小于国标规定的公众年剂量限值要求。结论 该焦化厂新装同位素装置场所基本符合国家规定。     

Development of a lyophilized soybean paste certified reference material for the analysis of ochratoxin A

A certified reference material (CRM) [²KRISS CRM # 108-10-018] for the analysis of ochratoxin A (OTA) in doenjang (fermented soybean paste and popular food in Korea) was produced to ensure the reliability of analytical results in testing laboratories. A home-made doenjang was chosen as a raw material after testing its OTA level. The raw material was freeze-dried, pulverized, sieved and homogenized. An isotope-dilution-liquid chromatography/tandem mass spectrometric method (ID-LC/MS/MS) which was previously developed and validated in this laboratory was used as a higher-order reference method for characterization, homogeneity studies, and short-term stability studies. The CRM had good between-bottle homogeneity with 0.56% relative standard deviation among 10 selected units. The stability of the CRM at −70 °C (the storage condition in our laboratory) and at −20 °C (the possible storage temperature at user sites) were tested for up to 8 months. No change in the OTA content was observed within the measurement uncertainty. The stability of the CRM at room temperature (for regular use and transportation) was also tested and confirmed. The certified value was (49.50 ± 1.17) μg/kg, where the expanded uncertainty was in the confidence level of 95%.     

67Ga显像对活动性肺结核的诊断价值

目的：探讨67Ga显像对活动性肺结核的诊断价值。方法：对160例非肿瘤患67Ga显像结果进行回顾性分析。诊断活动性肺结核100例，陈旧性肺结核26例，普通肺炎29例，淋巴结核5例，结果：活动性肺结核患67Ga阳性显像率72．00％（72／100），明显高于陈旧性肺结核23．08％（6／26）及普通肺炎17．24％（5／29），活动性肺结核患中， 痰菌阳性患67Ga阳性显像率79．73％（59／74），明显高于痰菌阴性50．00％（13／26），结论：67Ga显像可能在判断肺结核活动中具有一定价值。     

Reference antigen-free and antibody-free LTD-IDMS assay for influenza H7N9 vaccine in vitro potency determination

Influenza vaccines are the most effective intervention to prevent the substantial public health burden of seasonal and pandemic influenza. Hemagglutinin (HA), as the main antigen in inactivated influenza vaccines (IIVs), elicits functional neutralizing antibodies and largely determines IIV effectiveness. HA potency has been evaluated by single-radial immunodiffusion (SRID), the standard in vitro potency assay for IIVs, to predict vaccine immunogenicity with a correlation to protective efficacy. We previously reported that limited trypsin digestion (LTD) selectively degraded stressed HA, so that an otherwise conformationally insensitive biophysical quantification technique could specifically quantify trypsin-resistant, immunologically active HA. Here, we demonstrate that isotope dilution mass spectrometry (IDMS), a method capable of quantifying the absolute HA concentration without reference antigen use, can be further expanded by adding LTD followed with precipitation to selectively quantify the active HA. We test the LTD-IDMS assay on H7N9 vaccines stressed by low pH, raised temperature, or freeze/thaw cycles. This method, unlike SRID, has no requirement for strain-specific reference antigens or antibodies and can generate potency values that correlate with SRID. Thus, LTD-IDMS is a promising alternative in vitro potency assay for influenza vaccines to complement and potentially replace SRID in a pandemic when strain specific reagents may not be readily available.     

Regulation of pool sizes and turnover rates of amino acids in humans: 15N-glycine and 15N-alanine single-dose experiments using gas chromatography—Mass spectrometry analysis

Gas chromatography—mass spectrometry (GCMS) of plasma amino acid derivatives has been used to determine directly the ¹⁵N-enrichment of plasma glycine and alanine in ten volunteers at various metabolic states. Isotope-enrichment time-decay curves of plasma glycine and alanine, following a single intravenous dose of ¹⁵N-glycine or ¹⁵N-L-alanine were obtained and provide an estimate of the extracellular compartment. Relatively narrow ranges were obtained for the glycine pool ($\text{7.7–11.8 μ}\text{mole}\text{100 g}\text{body wt}$), rate constants of transport (3.7–4.2 hr^?1) and flux ($\text{28–43 μ}\text{mole hr}{}^{\mathrm{?1}}\text{100 g}\text{body wt}$) in the postabsorptive state. In postprandial humans, pool sizes showed only a modest variation whereas the rate constants of transport of glycine and alanine were significantly lower. The plasma ¹⁵N-glycine and ¹⁵N-alanine isotope-enrichment time-decay curves over the first hour following a single i.v. dose of ¹⁵N-amino acid represent mostly the hepatic uptake of glycine and alanine from the extracellular pool. The results presented in this study establish the stable isotope GCMS method as a more accurate, more convenient, and safe alternative to the use of radioactive labeled amino acids in studies of amino acid metabolism in human subjects.