Within the framework of the Protection of the Environment programme of the JRC-Ispra of the European Community, research on trace metal exposure and health effects is concerned primarily with the toxicological assessment of present levels of trace metals in the tissues of exposed and unexposed populations. Main activities are: (1) microdetermination of trace elements in human tissues in order to generate an accurate and reliable data base on the levels and biochemical forms of trace metals in differently exposed humans; (2) metabolism and biochemical mechanisms involving trace metals to assess the toxicological significance of the current levels of the elements in the human body. Few selected applications related to the different steps of the biochemical toxicology research are shown. They concern the long-term behaviour of trace metals at the target tissues of laboratory animals, the biological monitoring of vanadium in workers during maintenance operations at an oil fired power plant for energy production, and the biochemical mechanism of methylation of arsenic in vivo.
Authors:M. Cantone, D. De Bartolo, A. Giussani, L. Garlaschelli, Ch. Hansen, P. Roth, and E. Werner
In order to estimate gut absorption by determining tracer concentration in plasma, a technique based on the administration of two stable isotopes of the same element was combined with proton activation analysis. The optimization for the determination of Zr isotopes in biological samples is presented together with the results of a preliminary study on Zr biokinetics in animals. (p,n) reactions on90Zr and96Zr resulted the most convenient. The obtained minimum detectable quantities are 3 and 2 ng/ml plasma, respectively, for90Zr and96Zr. Zr plasma clearance and Zr response to a simple oral test were studied separately in different subjects by using the natural Zr solution. The data analysis was performed measuring the concentration of90Zr to obtain indication on the time behavior and fractional level of Zr appearance in plasma depending on the administration routes. Two rabbits were intravenously injected 50 g90Zr and a third rabbit was orally given 2.5 mg of90Zr. Concentration in plasma samples of intravenously and orally given Zr isotopes are reported, as a function of time after administration. The injected tracer concentration relative to the first two rabbits were fitted simultaneously to obtain clearance parameters. Zr intestinal absorption is evaluated to be less than 0.2%. The work confirms that proton activation is a powerful tool for biokinetic studies with stable isotopes.
Authors:Sabrina Metairon, Cibele Zamboni, Miriam Suzuki, Carlos Bueno, and Osvaldo Sant’Anna
Element concentrations in biological tissues of Dmdmdx/J and C57BL/6 J mice strains were determined using the neutron activation analysis technique. Samples of whole blood, bones
and organs (heart and muscle) of these strains were irradiated in the IEA–R1 nuclear reactor at IPEN-CNEN/SP (Brazil). To
perform this investigation biological samples of two-month-old adult females (n = 10) and males (n = 9) for Dmdmdx/J (dystrophic mice), and males (n = 12) for C57BL/6 J (control group), originally obtained from the Jackson Laboratory (Maine, USA) and further inbred at IPEN–CNEN/SP
(São Paulo, Brazil), were used. A significant change was observed in the analysis of the heart of dystrophic mice suggesting
that this dysfunction affects severely the heart muscle. These data may, in the future, contribute to the healthcare area,
in veterinary medicine and in the pharmaceutical industry allowing the evaluation of the best procedures in diagnosis, treatment
and investigations of neuromuscular diseases (muscular dystrophy) of patients through the use of animal models.
Authors:J. Domahidi, Péter Katica, and Judit Farkas
Domahidi, I., Egyed-Zsigmond, I., Kolozsvári, É., Peti, A.: The acute effect and histopathological changes produced by methol in experimental animals, (in Romanian), Revista Românâ de Medicina Muncii 48 (3-4), 10015-10019 (1998
Authors:Maria-Raluca Szabo, Dorina Chambre, and Cornelia Idiţoiu
, corresponding to the first stage of decomposition is the most important value for the characterization of vegetable or animal fats thermal stability, since based on the starting temperature of thermal decomposition, different types of oil stability and the
The definition of dose-response relationships in man is the essential requisite to set scientifically health protection standards
for the evaluation of a safe level exposure of humans to heavy metals. The derivation of these relationships requires sequential
multidisciplinary informations including data on metabolic patterns and biochemical effects in mammals. Unfortunately, sufficient
data are not available to establish dose-response curves expecially in long term-low level exposure conditions and a need
exists to gather such informations for each metal on absorption, distribution and excretion in laboratory animals and humans.
This paper: (1) discuss main problems related to the use of NAA in metallobiochemistry of present levels of trace elements;
(2) report data on the current applications of NAA in metallobiochemistry in relation to the work carried out in the context
of a project Heavy Metal Pollution of CEC JRC—Ispra. Applications deal with in vivo studies on laboratory animals, in vitro
studies on biochemical systems and experiments on tissues of human origin; (3) discuss the perspectives of the use of the
nuclear techniques in the environmental toxicology.