Sabbioni E, Girardi F
Sci Total Environ. 1977 Mar;7(2):145-79. doi: 10.1016/0048-9697(77)90005-5.
The chronic exposure of man to increasing amounts of heavy metals as a consequence of environmental pollution, requires accurate knowledge of how much the homeostatic control of trace elements can stand increased exposure to abnormal amounts of metal pollutants without alteration of the biochemical functions. This topic includes the study of the accumulation of metal pollutants in the body with the identification of metal biocomplexes under long term-low level exposure (LLE) conditions. Extremely sensitive analytical techniques are required for experimentation at the heavy metal levels which are typical of a polluted environment in order to assess the limits of physiological homeostatic controls. The possiblity of applying nuclear and radiochemical techniques, such as neutron activation analysis, multiple tracing, high resolution gamma-ray spectrometry and Cerenkov counting, coupled with biochemical techniques, such as gel filtration, ion-exchange chromatography, polyacrylamide gel electrophoresis and differential centrifugation, has been demonstrated in various typical applications in metallobiochemistry. The subject of the first part of this paper is the development and improvement of the techniques, dealing with potential metal binding components, such as metalloenzymes and nucleic acids chosen as models. The developments refer to: preparation of labelled metal pollutants with very high specific activity to label in vivo nanogram or subnanogram amounts of pollutant metals; neutron activation analysis of enzymes and nucleic acids with the aim of analyzing concentrations of many metal pollutants in the identified metal binding components of the microsamples; radiochemical methods including radiobiochemical techniques for multielement tracer experiments and for studying the interaction of heavy metas and metal binding components; development of complementary counting techniques. The in vivo applications are centered on biochemical studies on cadmium, in particular on the long term-low exposure experiment, which is under investigation at present, with the identification of both critical organs of accumulation and of the cadmium binding components. Results are given for biochemical mechanisms involving cadmium such as the stimulation of the "de novo" biosynthesis of rat liver and intestine cadmium binding proteins (CdBP) and on the systematic study of the interaction of metal pollutants and rat liver cadmium binding proteins itself. Preliminary data are also given for short term experiments dealing with the identification of cellular metal binding components for V, Se, Cd and Pb.
由于环境污染，人类长期接触越来越多的重金属，这就需要准确了解微量元素的稳态控制在不改变生化功能的情况下，能够承受多少异常量金属污染物的增加暴露。这个主题包括研究金属污染物在体内的积累以及在长期低水平暴露（LLE）条件下对金属生物复合物的鉴定。为了评估生理稳态控制的极限，在受污染环境中典型的重金属水平下进行实验需要极其灵敏的分析技术。核技术和放射化学技术，如中子活化分析、多重示踪、高分辨率γ射线光谱法和切伦科夫计数法，与生化技术，如凝胶过滤、离子交换色谱、聚丙烯酰胺凝胶电泳和差速离心法相结合的可能性，已在金属生物化学的各种典型应用中得到证明。本文第一部分的主题是技术的发展和改进，涉及潜在的金属结合成分，如选择作为模型的金属酶和核酸。这些发展包括：制备具有非常高比活度的标记金属污染物，以标记体内纳克或亚纳克量的污染物金属；对酶和核酸进行中子活化分析，目的是分析微量样品中已鉴定的金属结合成分中多种金属污染物的浓度；放射化学方法，包括用于多元素示踪实验和研究重金属与金属结合成分相互作用的放射生物化学技术；互补计数技术的发展。体内应用主要集中在镉的生化研究上，特别是目前正在进行的长期低暴露实验，该实验旨在确定积累的关键器官和镉结合成分。给出了涉及镉的生化机制的结果，如对大鼠肝脏和肠道镉结合蛋白（CdBP）“从头”生物合成的刺激，以及对金属污染物与大鼠肝脏镉结合蛋白本身相互作用的系统研究。还给出了关于钒、硒、镉和铅的细胞金属结合成分鉴定的短期实验的初步数据。
